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The California Families Project (CFP) is an ongoing longitudinal study of Mexican origin families in Northern California. This study uses community, school, family, and individual characteristics to examine developmental pathways that increase risk for and resilience to drug use in Mexican-origin youth. This study also examines the impact that economic disadvantage and cultural traditions have in Mexican-origin youth. The CFP includes a community-based sample of 674 families and children of Mexican origin living in Northern California, and includes annual assessments of parents and children. Participants with Mexican surnames were drawn at random from school rosters of students during the 2006-2007 and 2007-2008 school year. Data collection included multi-method assessments of a broad range of psychological, familial, scholastic, cultural, and neighborhood factors. Initiation of the research at age 10 was designed to assess the focal children before the onset of Alcohol, Tobacco, and Other Drug (ATOD) use, thus enabling the evaluation of how hypothesized risk and resilience mechanisms operate to exacerbate early onset during adolescence or help prevent its occurrence. This study includes a diversity of families that represent a wide range of incomes, education, family history, and family structures, including two-parent and single-parent families.

The accompanying data file consists of 674 family cases with each case representing a focal child and at least one parent (Two-parent: n=549, 82 percent; Single-parent: n=125, 18 percent). Of the 3,139 total variables, 839 pertain to the focal child, 1,376 correspond to the mother, and 908 items pertain to the father.

Please note: While the California Families Project is a longitudinal study, only the baseline data are currently available in this data collection.

The Flint Adolescent Study (FAS) interviewed 850 ninth graders in the four public high schools of Flint, MI. The study was conducted in collaboration with the Projects for Urban and Regional Affairs and Flint Community Schools. The goal of the study was to explore the protective factors associated with school dropout and alcohol and substance use. The study followed the youths for four years beginning in the Fall of 1994. The sample reflected the overall student body in the Flint high schools. In order to study those students most at risk for leaving school before graduation, individuals with grade point averages of 3.0 and below were selected.

Interviews were conducted face-to-face with each student at the school or in a community location for students who were out of school. Each interview took about one hour to complete. At the end of the interview students were asked to complete the last section of the questionnaire by themselves which contains questions about their drug use and sexual behavior.

Information obtained from the youths includes: participation in church, school, and community organizations; social support and influence of family and friends; self esteem and psychological well being; delinquent and violent behaviors; alcohol and substance use; sex behavior and child bearing; school attitudes and performance; and family structure and relationships. The Youths were asked to complete a brief questionnaire at the end of the interview about their alcohol and substance use, and sexual behavior. In years 3 and 4 questions also asked about driving behavior, attachment style, stress, mentoring, and racial identity. Data was also collected about parental education and occupation.

The Future of Families and Child Wellbeing Study (FFCWS, formerly known as the Fragile Families and Child Wellbeing Study) follows a cohort of nearly 5,000 children born in large, U.S. cities between 1998 and 2000. The study oversampled births to unmarried couples; and, when weighted, the data are representative of births in large U.S. cities at the turn of the century. The FFCWS was originally designed to address four questions of great interest to researchers and policy makers:

1. What are the conditions and capabilities of unmarried parents, especially fathers?
2. What is the nature of the relationships between unmarried parents?
3. How do children born into these families fare?
4. How do policies and environmental conditions affect families and children?

The FFCWS consists of interviews with mothers, fathers, and/or primary caregivers at birth and again when children are ages 1, 3, 5, 9, 15, and 22. The parent interviews collected information on attitudes, relationships, parenting behavior, demographic characteristics, health (mental and physical), economic and employment status, neighborhood characteristics, and program participation. Beginning at age 9, children were interviewed directly (either during the home visit or on the telephone). The direct child interviews collected data on family relationships, home routines, schools, peers, and physical and mental health, as well as health behaviors.

A collaborative study of the FFCWS, the In-Home Longitudinal Study of Pre-School Aged Children (In-Home Study) collected data from a subset of the FFCWS Core respondents at the Year 3 and 5 follow-ups to ask how parental resources in the form of parental presence or absence, time, and money influence children under the age of 5. The In-Home Study collected information on a variety of domains of the child's environment, including: the physical environment (quality of housing, nutrition and food security, health care, adequacy of clothing and supervision) and parenting (parental discipline, parental attachment, and cognitive stimulation). In addition, the In-Home Study also collected information on several important child outcomes, including anthropometrics, child behaviors, and cognitive ability. This information was collected through interviews with the child's primary caregiver, and direct observation of the child's home environment and the child's interactions with his or her caregiver.

Similar activities were conducted during the Year 9 follow-up. At the Year 15 follow-up, a condensed set of home visit activities were conducted with a subsample of approximately 1,000 teens. Teens who participated in the In-Home Study were also invited to participate in a Sleep Study and were asked to wear an accelerometer on their non-dominant wrist for seven consecutive days to track their sleep (Sleep Actigraphy Data) and that day's behaviors and mood (Daily Sleep Actigraphy and Diary Survey Data).

An additional collaborative study collected data from the child care provider (Year 3) and teacher (Years 9 and 15) through mail-based surveys. Saliva samples were collected at Year 9 and 15 (Biomarker file and Polygenic Scores). The Study of Adolescent Neural Development (SAND) COVID Study began data collection in May 2020 following the onset of the COVID-19 pandemic. It included online surveys with the young adult and their primary caregiver.

The FFCWS began its seventh wave of data collection in October 2020, around the focal child's 22nd birthday. Data collection and interviews continued through January 2024. The Year 22 wave included a young adult (YA) survey with the original focal child and a primary caregiver (PCG) survey. Data were also collected on the children of the original focal child (referred to as Generation 3, or G3).

In 2017, the FFCWS team announced the Fragile Families (FF) Challenge, a collaborative effort in which participants were tasked with using machine learning methods and FFCWS data (Baseline to Year 9) to build a model that would predict six key outcomes at Year 15. Materials used in the FF Challenge have been archived in this collection.

Documentation for these files is available on the FFCWS website under Data and Documentation. For details of updates made to the FFCWS data files, please see the project's Data Alerts page.

Data collection for the Future of Families and Child Wellbeing Study was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) of the National Institutes of Health under award numbers R01HD36916, R01HD39135, and R01HD40421, as well as a consortium of private foundations.

Below is the citation for use of the FFCWS data accessed through ICPSR. For information on additional citation requirements when using FFCWS in publications, please refer to this FAQ on the FFCWS project site.

The Los Angeles Metropolitan Area Surveys [LAMAS] 10, 1976 collection reflects data gathered in 1976 as part of the Los Angeles Metropolitan Area Surveys (LAMAS). The LAMAS, beginning in the spring of 1970, are a shared-time omnibus survey of Los Angeles County community members, usually repeated twice annually. The LAMAS were conducted ten times between 1970 and 1976 in an effort to develop a set of standard community profile measures appropriate for use in the planning and evaluation of public policy.

The LAMAS instruments, indexes, and scales were used to track the development and course of social indicators (including social, psychological, health, and economic variables) and the impact of public policy on the community. Questions in this survey cover respondents' attitudes toward the following topics: child abuse, parent-child relationships, right to privacy, and political participation. In addition, participating researchers were given the option of submitting questions to be asked in addition to the core items. These additional question topics include: accidents and emergencies, crime, and health care/relationship to doctors.

Demographic variables included in this dataset include age, marital status, religion, sex, education, occupation, income, geographic origin, and race.

This collection contains data from the Multi-site Family Study on Incarceration, Parenting and Partnering [MSF-IP]. The MSF-IP is an evaluation of a grant program funded by the Office of Family Assistance (OFA) within the U.S. Department of Health and Human Services (HHS), Administration for Children and Families (ACF) to promote or sustain healthy relationships and to strengthen families in which a father was incarcerated or otherwise involved with the criminal justice system (e.g., recently released or on parole or probation). From 2006-2011, grantees were required to serve justice-involved fathers and their committed partners with services to promote healthy marriage; they were also permitted to provide activities to support parenting and foster economic stability.

The MFS-IP evaluation was funded to document program implementation and the impact of programming on outcomes such as relationship quality and stability, parenting and co-parenting, family financial well-being, and recidivism. This collection includes data from the impact study, conducted across five grantees: the Indiana Department of Correction, the RIDGE Project (Ohio), the New Jersey Department of Corrections, the Osborne Association (New York), and the Minnesota Council on Crime and Justice. The collection includes de-identified interview data for 1,991 men and 1,482 intimate and co-parenting partners.

The interviews took place from December 2008 through August 2014. Couples were first interviewed during the male partner's incarceration (with the timing of baseline interviews not related to the man's admission or release date in most sites) and then interviewed again nine and 18 months after baseline. In the two largest sites (Indiana and Ohio), an additional 34-month follow-up interview was conducted. The interviews were similar in content at each interview wave and for the male and female interviews, but differed based on male partner's trajectory of incarceration and release over the follow-up period.

Topics within this collection include demographics, personal characteristics and attitudes, criminal history and behavior, incarceration experiences (including family contact during incarceration), program and service receipt, expectations for release, family structure and functioning, intimate relationship quality, parenting and co-parenting quality, child well-being, employment, housing, substance use, and experiences with reentry.

The National Comorbidity Survey Replication Adolescent Supplement (NCS-A) was designed to estimate the lifetime-to-date and current prevalence, age-of-onset distributions, course, and comorbidity of DSM-IV disorders in the child and adolescent years of life among adolescents in the United States; to identify risk and protective factors for the onset and persistence of these disorders; to describe patterns and correlates of service use for these disorders; and to lay the groundwork for subsequent follow-up studies that can be used to identify early expressions of adult mental disorders.

The core NCS-A interview schedule was an adaptation of the World Health Organization Composite International Diagnostic Interview (CIDI). NCS-A also administered the non-verbal subtest (Matrices subtest) of the Kaufman Brief Intelligence Test (K-BIT).

In addition to interviewing adolescents, information was collected from a parent or a parent surrogate to obtain an additional perspective on the adolescent's mental health and its correlates. Information from parents focused on the five adolescent disorders for which previous methodological research has most consistently shown that parental reports are important for making diagnoses: attention-deficit/hyperactivity disorder, conduct disorder, oppositional defiant disorder, major depressive episode, and dysthymic disorder.

Demographic information collected by NCS-A includes age, citizenship status, country of birth, criminal history, ethnicity, grandparents' country of birth, language(s) spoken in the home, parents' country of birth, race, religion, and sex.

The data collection contains six data files: (1) data for the adolescent household and school respondents; (2) data for the parents who responded to the long self-administered questionnaire; (3) data for the parents who responded to both the long self-administered questionnaire and short telephone interview; (4) diagnostic variables derived from the data collected from the adolescents and parents; (5) K-BIT scores normed to the NCS-A adolescent sample; and (6) raw K-BIT data.

The overall purpose of this study was to examine the influence of variations in early childcare histories on the psychological development of infants and toddlers from a variety of family backgrounds. This general objective was addressed through a prospective, longitudinal study of the experiences of 1,364 children and their families, which took into account the complex interactions among child characteristics and those of the human and physical environments in which the children were reared.

The specific research aims were as follows:

• Examining the relationship between infants' childcare arrangements (defined in terms of hours, type, quality, and stability of care and the age at which the child entered care) and children's concurrent and long-term development. Specifically, the study investigated the association between children's experiences in childcare and their social, emotional, language, and cognitive development. The social-emotional assessments included measures of attachment, independence, compliance, behavior problems, prosocial and antisocial behavior, and general competence in interacting with peers. Cognitive variables include general developmental level and problem solving skills. Language assessments incorporated measures of children's expressive and receptive communicative competence.

• Examining whether the social ecology of the home moderates the effects of childcare, i.e., whether children from different home environments are differentially affected by similar childcare experiences. The study examined the moderating effects of parents' values and attitudes, psychological adjustment and mental health, stress and social support, child-rearing practices, time use, interactions with the child, the marital relationship, and family demographics.

• Examining whether individual differences among children moderate the effects of infant care on child development. The study examined the moderating effects of such child characteristics as age, sex, health, birth order, and temperament.

• Identify demographic and family characteristics associated with families' childcare decisions. The study examined whether specific childcare arrangements are related to the parents' social class, marital status, psychological adjustment and personality, child-rearing values and attitudes, parenting practices, stress, social support, marital relationship, and the availability of childcare in the community.

• Provide a natural history of infant care in the 1990s, and help establish a baseline of data pertaining to the kinds of care being used by families. Whereas other national databases, such as those provided by the United States Census Bureau, provide static estimates of the number of children in different types of childcare, this network study supplements that knowledge with longitudinal data on successive enrollments into day care at various ages, patterns of arrangements used concurrently and over time, and the stability of arrangements during the first three years of life. One of the most valuable aspects of the collaborative study is the opportunity it provides to obtain a more complete and accurate picture of patterns of infant care used by families today. Census surveys use only gross categories of care (e.g., center vs. in-home). In this study, more fine-grained information regarding the types of centers and home-care facilities was gathered.

• Examine the consequences for families of maternal employment and childcare choices. Family relationships, parental mental health, family stress, and so on, are not just inputs to child development or moderators of childcare effects, they are also outcomes. High-quality childcare may alleviate family stress and enhance parental adjustment. Low-quality childcare may add to the stress parents experience. Although the main focus in the study was on the effect of childcare on the child, the study also examined the effect of childcare on the family.

• Identify demographic characteristics of childcare associated with childcare quality. Of interest to policy makers is another aspect of the study, the investigation of those regulatory characteristics that predict care of higher quality. These characteristics included the level and type of caregiver training, the size of the childcare group, the auspices of the childcare program (public/private, profit/nonprofit, independent/chain, employer-sponsored/church-based), whether the facility was licensed or unlicensed, the level of payment and fees, and whether the caregiver was a relative of the family.

309 data files were compiled for this study and are organized into 3 main groups:

1. Analytical Data Sets (ADS) -- The raw data were examined and composites defined by small groups of individual principal investigators according to the demographic, family, childcare, and child outcome content of the data. The psychometric and distributional qualities of the variables, along with site differences, were examined. A set of variables that were psychometrically and distributionally acceptable to be used in analytic analyses was designed to test the study hypotheses. These data files comprise Parts 1-42 of the study data material.

2. Supplemental Data Sets -- New and revised analysis variables as well as across-time mean scores and primary composites were produced as a supplement to the original Analytical Datasets. These data files comprise Parts 43-55 of the study data material.

3. Raw Data Sets -- The raw data were made available and comprise Parts 56-309 of the study data material.

A three-day summer training workshop on the SECCYD was put on by NICHD at the Inter-University Consortium for Political and Social Research in Ann Arbor, Michigan in 2010. The binder from that workshop, which includes the Powerpoint slides used during presentations, are freely available to the public as part of the study documentation.

The overall purpose of this study was to examine the influence of variations in early childcare histories on the psychological development of infants and toddlers from a variety of family backgrounds. This general objective was addressed through a prospective, longitudinal study of the experiences of 1,364 children and their families, which took into account the complex interactions among child characteristics and those of the human and physical environments in which the children were reared.

The specific research aims were as follows:

• Examining the relationship between infants' childcare arrangements (defined in terms of hours, type, quality, and stability of care and the age at which the child entered care) and children's concurrent and long-term development. Specifically, the study investigated the association between children's experiences in childcare and their social, emotional, language, and cognitive development. The social-emotional assessments included measures of attachment, independence, compliance, behavior problems, prosocial and antisocial behavior, and general competence in interacting with peers. Cognitive variables include general developmental level and problem solving skills. Language assessments incorporated measures of children's expressive and receptive communicative competence.

• Examining whether the social ecology of the home moderates the effects of childcare, i.e., whether children from different home environments are differentially affected by similar childcare experiences. The study examined the moderating effects of parents' values and attitudes, psychological adjustment and mental health, stress and social support, child-rearing practices, time use, interactions with the child, the marital relationship, and family demographics.

• Examining whether individual differences among children moderate the effects of infant care on child development. The study examined the moderating effects of such child characteristics as age, sex, health, birth order, and temperament.

• Identify demographic and family characteristics associated with families' childcare decisions. The study examined whether specific childcare arrangements are related to the parents' social class, marital status, psychological adjustment and personality, child-rearing values and attitudes, parenting practices, stress, social support, marital relationship, and the availability of childcare in the community.

• Provide a natural history of infant care in the 1990s, and help establish a baseline of data pertaining to the kinds of care being used by families. Whereas other national databases, such as those provided by the United States Census Bureau, provide static estimates of the number of children in different types of childcare, this network study supplements that knowledge with longitudinal data on successive enrollments into day care at various ages, patterns of arrangements used concurrently and over time, and the stability of arrangements during the first three years of life. One of the most valuable aspects of the collaborative study is the opportunity it provides to obtain a more complete and accurate picture of patterns of infant care used by families today. Census surveys use only gross categories of care (e.g., center vs. in-home). In this study, more fine-grained information regarding the types of centers and home-care facilities was gathered.

• Examine the consequences for families of maternal employment and childcare choices. Family relationships, parental mental health, family stress, and so on, are not just inputs to child development or moderators of childcare effects, they are also outcomes. High-quality childcare may alleviate family stress and enhance parental adjustment. Low-quality childcare may add to the stress parents experience. Although the main focus in the study was on the effect of childcare on the child, the study also examined the effect of childcare on the family.

• Identify demographic characteristics of childcare associated with childcare quality. Of interest to policy makers is another aspect of the study, the investigation of those regulatory characteristics that predict care of higher quality. These characteristics included the level and type of caregiver training, the size of the childcare group, the auspices of the childcare program (public/private, profit/nonprofit, independent/chain, employer-sponsored/church-based), whether the facility was licensed or unlicensed, the level of payment and fees, and whether the caregiver was a relative of the family.

193 data files were compiled for this study and are organized into 3 main groups:

1. Analytical Data Sets (ADS) -- The raw data were examined and composites defined by small groups of individual principal investigators according to the demographic, family, childcare, and child outcome content of the data. The psychometric and distributional qualities of the variables along with site differences were examined. A set of variables that was psychometrically and distributionally acceptable to be used in analytic analyses was designed to test the study hypotheses. These data files comprise Parts 1-24 of the study data material.

2. Supplemental Data Sets -- New and revised analysis variables as well as across-time mean scores and primary composites were produced as a supplement to the original Analytical Data Sets. These data files comprise Parts 25-27 of the study data material.

3. Raw Data Sets -- The raw data were made available and comprise Parts 28-193 of the study data material.

A three-day summer training workshop on the SECCYD was put on by NICHD at the Inter-University Consortium for Political and Social Research in Ann Arbor, Michigan in 2010. The binder from that workshop, which includes the Powerpoint slides used during presentations, are freely available to the public as part of the study documentation.

The overall purpose of this study was to examine the influence of variations in early childcare histories on the psychological development of infants and toddlers from a variety of family backgrounds. This general objective was addressed through a prospective, longitudinal study of the experiences of 1,364 children and their families, which took into account the complex interactions among child characteristics and those of the human and physical environments in which the children were reared.

The specific research aims were as follows:

• Examining the relationship between infants' childcare arrangements (defined in terms of hours, type, quality, and stability of care and the age at which the child entered care) and children's concurrent and long-term development. Specifically, the study investigated the association between children's experiences in childcare and their social, emotional, language, and cognitive development. The social-emotional assessments included measures of attachment, independence, compliance, behavior problems, prosocial and antisocial behavior, and general competence in interacting with peers. Cognitive variables include general developmental level and problem solving skills. Language assessments incorporated measures of children's expressive and receptive communicative competence.

• Examining whether the social ecology of the home moderates the effects of childcare, i.e., whether children from different home environments are differentially affected by similar childcare experiences. The study examined the moderating effects of parents' values and attitudes, psychological adjustment and mental health, stress and social support, child-rearing practices, time use, interactions with the child, the marital relationship, and family demographics.

• Examining whether individual differences among children moderate the effects of infant care on child development. The study examined the moderating effects of such child characteristics as age, sex, health, birth order, and temperament.

• Identify demographic and family characteristics associated with families' childcare decisions. The study examined whether specific childcare arrangements are related to the parents' social class, marital status, psychological adjustment and personality, child-rearing values and attitudes, parenting practices, stress, social support, marital relationship, and the availability of childcare in the community.

• Provide a natural history of infant care in the 1990s, and help establish a baseline of data pertaining to the kinds of care being used by families. Whereas other national databases, such as those provided by the United States Census Bureau, provide static estimates of the number of children in different types of childcare, this network study supplements that knowledge with longitudinal data on successive enrollments into day care at various ages, patterns of arrangements used concurrently and over time, and the stability of arrangements during the first three years of life. One of the most valuable aspects of the collaborative study is the opportunity it provides to obtain a more complete and accurate picture of patterns of infant care used by families today. Census surveys use only gross categories of care (e.g., center vs. in-home). In this study, more fine-grained information regarding the types of centers and home-care facilities was gathered.

• Examine the consequences for families of maternal employment and childcare choices. Family relationships, parental mental health, family stress, and so on, are not just inputs to child development or moderators of childcare effects, they are also outcomes. High-quality childcare may alleviate family stress and enhance parental adjustment. Low-quality childcare may add to the stress parents experience. Although the main focus in the study was on the effect of childcare on the child, the study also examined the effect of childcare on the family.

• Identify demographic characteristics of childcare associated with childcare quality. Of interest to policy makers is another aspect of the study, the investigation of those regulatory characteristics that predict care of higher quality. These characteristics included the level and type of caregiver training, the size of the childcare group, the auspices of the childcare program (public/private, profit/nonprofit, independent/chain, employer-sponsored/church-based), whether the facility was licensed or unlicensed, the level of payment and fees, and whether the caregiver was a relative of the family.

504 data files were compiled for this study and are organized into 4 main groups:

1. Analytical Data Sets (ADS) -- The raw data were examined and composites defined by small groups of individual principal investigators according to the demographic, family, childcare, and child outcome content of the data. The psychometric and distributional qualities of the variables along with site differences were examined. A set of variables that was psychometrically and distributionally acceptable to be used in analytic analyses was designed to test the study hypotheses. These data files comprise Parts 1-49 of the study data material.

2. Supplemental Data Sets -- New and revised analysis variables as well as across-time mean scores and primary composites were produced as a supplement to the original Analytical Data Sets. These data files comprise Parts 50-55 of the study data material.

3. Raw Census-Related Data Sets -- Files were produced using geocoded addresses for survey respondents to match block group level data from the 1990 and 2000 Censuses for investigators to create additional measures of interest from the geocoded addresses. These data files comprise Parts 56-58 of the study data material.

4. Raw Data Sets -- The raw data were made available and comprise Parts 59-505 of the study data material.

A three-day summer training workshop on the SECCYD was put on by NICHD at the Inter-University Consortium for Political and Social Research in Ann Arbor, Michigan in 2010. The binder from that workshop, which includes the Powerpoint slides used during presentations, are freely available to the public as part of the study documentation.

The overall purpose of this study was to examine the influence of variations in early childcare histories on the psychological development of infants and toddlers from a variety of family backgrounds. This general objective was addressed through a prospective, longitudinal study of the experiences of 1,364 children and their families, which took into account the complex interactions among child characteristics and those of the human and physical environments in which the children were reared.

The specific research aims were as follows:

• Examining the relationship between infants' childcare arrangements (defined in terms of hours, type, quality, and stability of care and the age at which the child entered care) and children's concurrent and long-term development. Specifically, the study investigated the association between children's experiences in childcare and their social, emotional, language, and cognitive development. The social-emotional assessments included measures of attachment, independence, compliance, behavior problems, prosocial and antisocial behavior, and general competence in interacting with peers. Cognitive variables include general developmental level and problem solving skills. Language assessments incorporated measures of children's expressive and receptive communicative competence.

• Examining whether the social ecology of the home moderates the effects of childcare, i.e., whether children from different home environments are differentially affected by similar childcare experiences. The study examined the moderating effects of parents' values and attitudes, psychological adjustment and mental health, stress and social support, child-rearing practices, time use, interactions with the child, the marital relationship, and family demographics.

• Examining whether individual differences among children moderate the effects of infant care on child development. The study examined the moderating effects of such child characteristics as age, sex, health, birth order, and temperament.

• Identify demographic and family characteristics associated with families' childcare decisions. The study examined whether specific childcare arrangements are related to the parents' social class, marital status, psychological adjustment and personality, child-rearing values and attitudes, parenting practices, stress, social support, marital relationship, and the availability of childcare in the community.

• Provide a natural history of infant care in the 1990s, and help establish a baseline of data pertaining to the kinds of care being used by families. Whereas other national databases, such as those provided by the United States Census Bureau, provide static estimates of the number of children in different types of childcare, this network study supplements that knowledge with longitudinal data on successive enrollments into day care at various ages, patterns of arrangements used concurrently and over time, and the stability of arrangements during the first three years of life. One of the most valuable aspects of the collaborative study is the opportunity it provides to obtain a more complete and accurate picture of patterns of infant care used by families today. Census surveys use only gross categories of care (e.g., center vs. in-home). In this study, more fine-grained information regarding the types of centers and home-care facilities was gathered.

• Examine the consequences for families of maternal employment and childcare choices. Family relationships, parental mental health, family stress, and so on, are not just inputs to child development or moderators of childcare effects, they are also outcomes. High-quality childcare may alleviate family stress and enhance parental adjustment. Low-quality childcare may add to the stress parents experience. Although the main focus in the study was on the effect of childcare on the child, the study also examined the effect of childcare on the family.

• Identify demographic characteristics of childcare associated with childcare quality. Of interest to policy makers is another aspect of the study, the investigation of those regulatory characteristics that predict care of higher quality. These characteristics included the level and type of caregiver training, the size of the childcare group, the auspices of the childcare program (public/private, profit/nonprofit, independent/chain, employer-sponsored/church-based), whether the facility was licensed or unlicensed, the level of payment and fees, and whether the caregiver was a relative of the family.

158 data files were compiled for this study and are organized into 4 main groups:

1. Analytical Data Sets (ADS)-- The raw data were examined and composites defined by small groups of individual principal investigators according to the demographic, family, childcare, and child outcome content of the data. The psychometric and distributional qualities of the variables along with site differences were examined. A set of variables that was psychometrically and distributionally acceptable to be used in analytic analyses was designed to test the study hypotheses. These data files comprise Parts 1-19 of the study data material.

2. Supplemental Data Sets -- New and revised analysis variables as well as across-time mean scores and primary composites were produced as supplements to the original Analytical Data Sets. These data files are Parts 20-26 of the study data material.

3. Raw Census-Related Data Sets -- Files were produced using geocoded addresses for survey respondents to match block group-level data from the 1990 and 2000 Censuses for investigators to create additional measures of interest from the geocoded addresses. These data files comprise Parts 27-30 of the study data material.

4. Raw Data Sets -- The raw data were made available and comprise Parts 31-158 of the study data material.

Included in this phase of the study are the output of several third-party software programs that were used during Phases II, III and IV to collect data for specific tasks or activities. These programs produced one output data file per subject, which were combined to produce some of the raw data files for those studies. The original program output is included as expanded documentation in this phase of the study.

A three-day summer training workshop on the SECCYD was put on by NICHD at the Inter-University Consortium for Political and Social Research in Ann Arbor, Michigan in 2010. The binder from that workshop, which includes the Powerpoint slides used during presentations, are freely available to the public as part of the study documentation.

The Oregon Youth Substance Use Project (OYSUP) began in 1998, with the recruitment of 1,075 first through fifth graders within a single school district in a working class community in western Oregon. Youth were followed from early childhood (1st through 5th grade), through adolescence, and into emerging adulthood (at age 20-22), with additional data collection at age 20 to 26. The primary objective of OYSUP was to identify risk and protective factors predictive of or comorbid with the development of substance use and at-risk sexual behaviors. OYSUP consisted of a multi-method annual assessment of etiological factors across numerous contextual (e.g., family, peer, neighborhood and school) and individual (personality, biological) domains, predictive of children's cognitions regarding substance use, their own substance use and their at-risk sexual behaviors (beginning in middle school). This unique study follows a representative sample of youth with approximately annual assessments from early childhood, through adolescence, and into emerging adulthood (at age 20-22). The primary objective of the original project and its renewals is to identify risk and protective factors predictive of or comorbid with the development of substance use and at-risk sexual behaviors.

Quantitative survey data was collected from each respondent from 1998 to 2014. Within the aims of the original OYSUP study and the three subsequent renewals, participants and their parents were followed annually until they were one-year post-high school, with an additional intensive assessment at age 20-22. In each year, the target participant and their parents completed assessments. The intensive assessment at age 20-22 included a diagnostic interview with the target participants and an assessment of cortisol reactivity in response to acute stress. During the school years, teachers completed assessments assessing their student's behavior, and school records for most students were obtained each year. In addition, principals in elementary schools completed school climate assessments and census data is used to obtain measures of neighborhood climate. In the third renewal, questionnaires and interviews were given across a two-year span, when participants were aged 20 to 26. The goal of this supplement was to investigate the factors leading to e-cigarette use and and use of other novel tobacco products across two years. Finally, respondents' demographic information was also collected.

The Population Assessment of Tobacco and Health (PATH) Study began originally surveying 45,971 adult and youth respondents. The PATH Study was launched in 2011 to inform Food and Drug Administration's regulatory activities under the Family Smoking Prevention and Tobacco Control Act (TCA). The PATH Study is a collaboration between the National Institute on Drug Abuse (NIDA), National Institutes of Health (NIH), and the Center for Tobacco Products (CTP), Food and Drug Administration (FDA). The study sampled over 150,000 mailing addresses across the United States to create a national sample of people who use or do not use tobacco.

45,971 adults and youth constitute the first (baseline) wave of data collected by this longitudinal cohort study. These 45,971 adults and youth along with 7,207 "shadow youth" (youth ages 9 to 11 sampled at Wave 1) make up the 53,178 participants that constitute the Wave 1 Cohort. Respondents are asked to complete an interview at each follow-up wave. Youth who turn 18 by the current wave of data collection are considered "aged-up adults" and are invited to complete the Adult Interview. Additionally, "shadow youth" are considered "aged-up youth" upon turning 12 years old, when they are asked to complete an interview after parental consent.

At Wave 4, a probability sample of 14,098 adults, youth, and shadow youth ages 10 to 11 was selected from the civilian, noninstitutionalized population at the time of Wave 4. This sample was recruited from residential addresses not selected for Wave 1 in the same sampled Primary Sampling Units (PSUs) and segments using similar within-household sampling procedures. This "replenishment sample" was combined for estimation and analysis purposes with Wave 4 adult and youth respondents from the Wave 1 Cohort who were in the civilian, noninstitutionalized population at the time of Wave 4. This combined set of Wave 4 participants, 52,731 participants in total, forms the Wave 4 Cohort.

Dataset 0001 (DS0001) contains the data from the Master Linkage file. This file contains 14 variables and 67,276 cases. The file provides a master list of every person's unique identification number and what type of respondent they were for each wave.

At Wave 7, a probability sample of 14,863 adults, youth, and shadow youth ages 9 to 11 was selected from the civilian, noninstitutionalized population at the time of Wave 7. This sample was recruited from residential addresses not selected for Wave 1 or Wave 4 in the same sampled PSUs and segments using similar within-household sampling procedures. This second replenishment sample was combined for estimation and analysis purposes with Wave 7 adult and youth respondents from the Wave 4 Cohort who were at least age 15 and in the civilian, noninstitutionalized population at the time of Wave 7. This combined set of Wave 7 participants, 46,169 participants in total, forms the Wave 7 Cohort.

Please refer to the Public-Use Files User Guide that provides further details about children designated as "shadow youth" and the formation of the Wave 1, Wave 4, and Wave 7 Cohorts.

Dataset 1001 (DS1001) contains the data from the Wave 1 Adult Questionnaire. This data file contains 1,732 variables and 32,320 cases. Each of the cases represents a single, completed interview.

Dataset 1002 (DS1002) contains the data from the Youth and Parent Questionnaire. This file contains 1,228 variables and 13,651 cases.

Dataset 2001 (DS2001) contains the data from the Wave 2 Adult Questionnaire. This data file contains 2,197 variables and 28,362 cases. Of these cases, 26,447 also completed a Wave 1 Adult Questionnaire. The other 1,915 cases are "aged-up adults" having previously completed a Wave 1 Youth Questionnaire.

Dataset 2002 (DS2002) contains the data from the Wave 2 Youth and Parent Questionnaire. This data file contains 1,389 variables and 12,172 cases. Of these cases, 10,081 also completed a Wave 1 Youth Questionnaire. The other 2,091 cases are "aged-up youth" having previously been sampled as "shadow youth."

Dataset 3001 (DS3001) contains the data from the Wave 3 Adult Questionnaire. This data file contains 2,139 variables and 28,148 cases. Of these cases, 26,241 are continuing adults having completed a prior Adult Questionnaire. The other 1,907 cases are "aged-up adults" having previously completed a Youth Questionnaire.

Dataset 3002 (DS3002) contains the data from the Wave 3 Youth and Parent Questionnaire. This data file contains 1,309 variables and 11,814 cases. Of these cases, 9,769 are continuing youth having completed a prior Youth Interview. The other 2,045 cases are "aged-up youth" having previously been sampled as "shadow youth."

Datasets 3101, 3102, 3201 and 3202 (DS3101, DS3102, DS3201, and DS3202) are data files comprising the weight variables for Wave 3. The weight variables for Wave 1 and Wave 2 are included in the main data files. However, in Wave 3, the weight variables have been separated into individual data files for Adult and Youth Questionnaires. The "all-waves" weight files contain weights for those respondents who have completed an interview during all three waves of data collection. The "single-wave" weight files contain weights for all respondents in Wave 3 regardless of their participation in previous waves.

Dataset 3503 (DS3503) contains data derived from responses to Wave 1-3 questionnaires indicating if participants had ever/never used various tobacco products as of the Wave 3 study period. This data file contains 25 variables for all 53,178 study participants as of Wave 3. This file is provided for reference only to simplify the definitions of tobacco use variables in the Adult and Youth data files for subsequent waves.

Dataset 4001 (DS4001) contains the data from the Wave 4 Adult Questionnaire. This data file contains 2,182 variables and 33,822 cases. Of these cases, 25,857 are continuing adults having completed a prior Adult Questionnaire, 1,900 are "aged-up adults" having previously completed a Youth Questionnaire, and 6,065 are "replenishment sample adults" (also known as "new cohort adults" in the annotated instrument).

Dataset 4002 (DS4002) contains the data from the Wave 4 Youth and Parent Questionnaire. This data file contains 1,389 variables and 14,798 cases. Of these cases, 9,365 are continuing youth having completed a prior Youth Interview, 1,694 cases are "aged-up youth" having previously been sampled as "shadow youth," and 3,739 are "replenishment sample youth" (also known as "new cohort youth" in the annotated instrument).

Datasets 4111, 4112, 4211, 4212, 4321, and 4322 (DS4111, DS4112, DS4211, DS4212, DS4321, and DS4322) are data files comprising the weight variables for Wave 4. In Wave 4, the weight variables have been separated into individual data files corresponding to the Wave 1 and Wave 4 Cohorts and different weight types. The "all-waves" weight files contain weights for those Wave 1 Cohort respondents who completed an interview for all waves in which they were old enough or verified their information for waves in which they were not old enough to be interviewed. The "single-wave" weight files contain weights for Wave 1 Cohort respondents at Wave 4 who completed an interview at Wave 1, regardless of their participation in previous waves. The "cross-sectional" weight files contain weights for all respondents in the Wave 4 Cohort.

Dataset 4503 (DS4503) contains data derived from responses to Wave 1-4 questionnaires indicating if participants had ever/never used various tobacco products as of the Wave 4 data collection period. This data file contains 27 variables for all 67,276 study participants as of the Wave 4 data collection. This file is provided for reference only to simplify the definitions of tobacco use variables in the Adult and Youth data files for subsequent waves.

Dataset 5001 (DS5001) contains the data from the Wave 5 Adult Questionnaire. This data file contains 2,315 variables and 34,309 cases. Of these cases, 29,876 are continuing adults having completed a prior Adult Questionnaire, 4,433 are "aged-up adults" having previously completed a Youth Questionnaire.

Dataset 5002 (DS5002) contains the data from the Wave 5 Youth and Parent Questionnaire. This data file contains 1,530 variables and 12,098 cases. Of these cases, 10,446 are continuing youth having completed a prior Youth Interview, 1,652 cases are "aged-up youth" having previously been sampled as "shadow youth."

Datasets 5111, 5112, 5211, 5212, 5221, 5222, 5711, 5712, 5721, and 5722 (DS5111, DS5112, DS5211, DS5212, DS5221, DS5222, DS5711, DS5712, DS5721, and DS5722) are data files comprising the weight variables for Wave 5. In Wave 5, the weight variables are in individual data files corresponding to the Wave 1 and Wave 4 Cohorts and different weight types. The "all-waves" weight files contain weights for those Wave 1 Cohort participants who completed a Wave 5 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, and 4.

Dataset 5503 (DS5503) contains data derived from responses to Wave 1-5 (including Wave 4.5) questionnaires indicating if participants had ever/never used various tobacco products as of the Wave 5 data collection period. This data file contains 26 variables for all 67,276 study participants as of the Wave 5 data collection. This file is provided for reference only to simplify the definitions of tobacco use variables in the Adult and Youth data files for subsequent waves.

There are two separate sets of files with "single wave" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "single-wave" weight files for the Wave 1 Cohort contain weights for participants who completed an interview in Wave 1 and in Wave 5, regardless of their participation in the intervening waves. The "single-wave" weight files for the Wave 4 Cohort contain weights for all Wave 5 interview respondents in the Wave 4 Cohort.

There are also two separate sets of files with "special collection all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "special collection all-waves" weight files for the Wave 1 Cohort contains weights for participants who completed a Wave 5 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, and the special collection in Wave 4.5. The "special collection all-waves" weight files for the Wave 4 Cohort contain weights for participants who completed a Wave 5 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Wave 4 and the special collection in Wave 4.5.

Dataset 6001 (DS6001) contains the data from the Wave 6 Adult Questionnaire. This data file contains 2,589 variables and 30,516 cases. Of these cases, 28,852 are continuing adults having completed a prior Adult Questionnaire and 1,664 are "aged-up adults" having previously completed a Youth Questionnaire.

Dataset 6002 (DS6002) contains the data from the Wave 6 Youth and Parent Questionnaire. This data file contains 1,822 variables and 5,652 cases. Of these cases, 5,622 are continuing youth having completed a prior Youth interview and 30 cases are "aged-up youth" having previously been sampled as "shadow youth."

Datasets 6111, 6112, 6121, 6122, 6211, 6212, 6221, 6222, 6711, 6712, 6721, and 6722 (DS6111, DS6112, DS6121, DS6122, DS6211, DS6212, DS6221, DS6222, DS6711, DS6712, DS6721, and DS6722) are data files comprising the weight variables for Wave 6. In Wave 6, the weight variables are in individual data files corresponding to the Wave 1 and Wave 4 Cohorts and different weight types. There are two separate sets of files with "all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "all-waves" weight files for the Wave 1 Cohort contain weights for participants who completed a Wave 6 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, and 5. The "all-waves" weight files for the Wave 4 Cohort contain weights for participants who completed a Wave 6 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4 and 5.

There are two separate sets of files with "single-wave" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "single-wave" weight files for the Wave 1 Cohort contain weights for participants who completed an interview in Wave 1 and in Wave 6, regardless of their participation in the intervening waves. The "single-wave" weight files for the Wave 4 Cohort contain weights for participants who completed an interview in Wave 4 and in Wave 6, regardless of their participation in the intervening waves.

There are also two separate sets of files with "special collection all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "special collection all-waves" weight files for the Wave 1 Cohort contain weights for participants who completed a Wave 6 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, 5, and the special collections in Wave 4.5, and Wave 5.5 or PATH-ATS. The "special collection all-waves" weight files for the Wave 4 Cohort contain weights for participants who completed a Wave 6 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4 and 5, and the special collections in Wave 4.5, and Wave 5.5 or PATH-ATS.

Dataset 6503 (DS6503) contains data derived from responses to Wave 1-6 (including Wave 4.5, Wave 5.5, and PATH-ATS) questionnaires indicating if participants had ever/never used various tobacco products as of the Wave 6 data collection period. This data file contains 24 variables for all 67,276 study participants as of the Wave 6 data collection. This file is provided for reference only to simplify the definitions of tobacco use variables in the Adult and Youth data files for subsequent waves.

Dataset 7001 (DS7001) contains the data from the Wave 7 Adult Questionnaire. This data file contains 2,813 variables and 30,801 cases. Of these cases, 27,258 are continuing adults having completed a prior Adult Questionnaire, 1,740 are "aged-up adults" having previously completed a Youth Questionnaire, and 1,803 are "replenishment sample adults" (also known as "new cohort adults" in the annotated instrument).

Dataset 7002 (DS7002) contains the data from the Wave 7 Youth and Parent Questionnaire. This data file contains 1,897 variables and 10,834 cases. Of these cases, 3,512 are continuing youth having completed a prior Youth Interview, 1 case is an "aged-up youth" having previously been sampled as "shadow youth," and 7,321 are "replenishment sample youth" (also known as "new cohort youth" in the annotated instrument).

Datasets 7111, 7112, 7121, 7122, 7211, 7212, 7221, 7222, 7331, 7332, 7711, 7712, 7721, and 7722 (DS DS7111, DS7112, DS7121, DS7122, DS7211, DS7212, DS7221, DS7222, DS7331, DS7332, DS7711, DS7712, DS7721, and DS7722) are data files comprising the weight variables for Wave 7. In Wave 7, the weight variables are in individual data files corresponding to the Wave 1, Wave 4, and Wave 7 Cohorts and different weight types.

There are two separate sets of files with "all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "all-waves" weight files for the Wave 1 Cohort contain weights for participants who completed a Wave 7 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, 5, and 6. The "all-waves" weight files for the Wave 4 Cohort contain weights for participants who completed a Wave 7 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4, 5, and 6.

There are two separate sets of files with "single-wave" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "single-wave" weight files for the Wave 1 Cohort contain weights for participants who completed an interview in Wave 1 and in Wave 7, regardless of their participation in the intervening waves. The "single-wave" weight files for the Wave 4 Cohort contain weights for participants who completed an interview in Wave 4 and in Wave 7, regardless of their participation in the intervening waves.

There are also two separate sets of files with "special collection all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "special collection all-waves" weight files for the Wave 1 Cohort contain weights for participants who completed a Wave 7 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, 5, 6, and the special collections in Wave 4.5, and Wave 5.5 or PATH-ATS. The "special collection all-waves" weight files for the Wave 4 Cohort contain weights for participants who completed a Wave 7 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4, 5, 6, and the special collections in Wave 4.5, and Wave 5.5 or PATH-ATS.

The "cross-sectional" weight files contain weights for all respondents in the Wave 7 Cohort.

Dataset 8001 (DS8001) contains data from the Wave 8 Adult Questionnaire. This data file contains 3,467 variables and 31,477 cases. Of these cases, 30,021 are continuing adults having completed a prior Adult Questionnaire and 1,456 are "aged-up adults" having previously completed a Youth Questionnaire.

Dataset 8002 (DS8002) contains data from the Wave 8 Youth and Parent Questionnaire. This data file contains 2,393 variables and 8,002 cases. Of these cases, 7,046 are continuing youth having completed a prior Youth Interview and 956 are "aged-up youth" having previously been sampled as "shadow youth."

Datasets 8111, 8121, 8122, 8211, 8221, 8231, 8232, 8711, 8721, 8722, 8731, and 8732 (DS8111, DS8121, DS8122, DS8211, DS8221, DS8231, DS8232, DS8711, 8DS721, DS8722, DS8731, and DS8732) are data files comprising the weight variables for Wave 8. In Wave 8, the weight variables are in individual data files corresponding to the Wave 1, Wave 4, and Wave 7 Cohorts and different weight types.

There are two separate sets of files with "all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "all-waves" weight files for the Wave 1 Cohort contain weights for participants who completed a Wave 8 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, 5, 6, and 7. Note that only adults have "all-waves" weights for the Wave 1 Cohort; youth from the Wave 1 Cohort aged-up to adults by the time of Wave 8. The "all-waves" weight files for the Wave 4 Cohort contain weights for participants who completed a Wave 8 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4, 5, 6, and 7.

There are three separate sets of files with "single-wave" weights: one for the Wave 1 Cohort, one for the Wave 4 Cohort, and one for the Wave 7 Cohort. The "single-wave" weight files for the Wave 1 Cohort contain weights for participants who completed an interview in Wave 1 and in Wave 8, regardless of their participation in the intervening waves. The "single-wave" weight files for the Wave 4 Cohort contain weights for participants who completed an interview in Wave 4 and in Wave 8, regardless of their participation in the intervening waves. Note that only adults have "single-wave" weights for the Wave 1 and Wave 4 Cohorts; youth from the Wave 1 Cohort aged-up to adults by the time of Wave 8 and youth from the Wave 4 Cohort were selected as shadow youth so they do not have any interview data from Wave 4. The "single wave" weights files for the Wave 7 Cohort contain weights for participants who completed an interview in Wave 7 and in Wave 8.

There are also three separate sets of files with "special collection all-waves" weights: one for the Wave 1 Cohort, one for the Wave 4 Cohort, and one for the Wave 7 Cohort. The "special collection all-waves" weight files for the Wave 1 Cohort contain weights for participants who completed a Wave 8 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, 5, 6, 7 and the special collections in Wave 4.5, Wave 5.5, and Wave 7.5. Note that only adults have "special collection all-waves" weights for the Wave 1 Cohort; youth from the Wave 1 Cohort aged-up to adults by the time of Wave 8. The "special collection all-waves" weight files for the Wave 4 Cohort contain weights for participants who completed a Wave 8 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4, 5, 6, 7, and the special collections in Wave 4.5, Wave 5.5, and Wave 7.5. The "special collection all-waves" weight files for the Wave 7 Cohort contain weights for participants who completed a Wave 8 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Wave 7 and the special collection in Wave 7.5.

Each case in an Adult data file represents a single, completed interview. Each case in a Youth data file represents one youth and his or her parent's responses about that youth. Parents who provided permission for their child to participate in a Youth Interview were asked to complete a brief interview about their child. In all waves of data collection, less than 0.5 percent of the parents did not complete an interview. Most questions are asked about the child.

When multiple youth from the same household were selected to be in the study, the parent(s) completed separate interviews about each youth. If one parent completed two or more interviews, that parent only answered questions about himself/herself once. Those questions were then skipped in the subsequent interview(s) for the other child(ren) and the responses duplicated in that child(ren)'s data file(s).

The PATH Study was launched in 2011 to inform the Food and Drug Administration's regulatory activities under the Family Smoking Prevention and Tobacco Control Act (TCA). The PATH Study is a collaboration between the National Institute on Drug Abuse (NIDA), National Institutes of Health (NIH), and the Center for Tobacco Products (CTP), Food and Drug Administration (FDA). The study sampled over 150,000 mailing addresses across the United States to create a national sample of people who use or do not use tobacco.

45,971 adults and youth constitute the first (baseline) wave, Wave 1, of data collected by this longitudinal cohort study. These 45,971 adults and youth along with 7,207 "shadow youth" (youth ages 9 to 11 sampled at Wave 1) make up the 53,178 participants that constitute the Wave 1 Cohort. Respondents are asked to complete an interview at each follow-up wave. Youth who turn 18 by the current wave of data collection are considered "aged-up adults" and are invited to complete the Adult Interview. Additionally, "shadow youth" are considered "aged-up youth" upon turning 12 years old, when they are asked to complete an interview after parental consent.

At Wave 4, a probability sample of 14,098 adults, youth, and shadow youth ages 10 to 11 was selected from the civilian, noninstitutionalized population (CNP) at the time of Wave 4. This sample was recruited from residential addresses not selected for Wave 1 in the same sampled Primary Sampling Units (PSUs) and segments using similar within-household sampling procedures. This "replenishment sample" was combined for estimation and analysis purposes with Wave 4 adult and youth respondents from the Wave 1 Cohort who were in the CNP at the time of Wave 4. This combined set of Wave 4 participants, 52,731 participants in total, forms the Wave 4 Cohort.

At Wave 7, a probability sample of 14,863 adults, youth, and shadow youth ages 9 to 11 was selected from the CNP at the time of Wave 7. This sample was recruited from residential addresses not selected for Wave 1 or Wave 4 in the same sampled PSUs and segments using similar within-household sampling procedures. This "second replenishment sample" was combined for estimation and analysis purposes with the Wave 7 adult and youth respondents from the Wave 4 Cohort who were at least age 15 and in the CNP at the time of Wave 7. This combined set of Wave 7 participants, 46,169 participants in total, forms the Wave 7 Cohort.

Please refer to the Restricted-Use Files User Guide that provides further details about children designated as "shadow youth" and the formation of the Wave 1, Wave 4, and Wave 7 Cohorts.

Dataset 0002 (DS0002) contains the data from the State Design Data. This file contains 7 variables and 82,139 cases. The state identifier in the State Design file reflects the participant's state of residence at the time of selection and recruitment for the PATH Study.

Dataset 1011 (DS1011) contains the data from the Wave 1 Adult Questionnaire. This data file contains 2,021 variables and 32,320 cases. Each of the cases represents a single, completed interview.

Dataset 1012 (DS1012) contains the data from the Wave 1 Youth and Parent Questionnaire. This file contains 1,431 variables and 13,651 cases.

Dataset 1411 (DS1411) contains the Wave 1 State Identifier data for Adults and has 5 variables and 32,320 cases. Dataset 1412 (DS1412) contains the Wave 1 State Identifier data for Youth (and Parents) and has 5 variables and 13,651 cases. The same 5 variables are in each State Identifier dataset, including PERSONID for linking the State Identifier to the questionnaire and biomarker data and 3 variables designating the state (state Federal Information Processing System (FIPS), state abbreviation, and full name of the state). The State Identifier values in these datasets represent participants' state of residence at the time of Wave 1, which is also their state of residence at the time of recruitment.

Dataset 1611 (DS1611) contains the Tobacco Universal Product Code (UPC) data from Wave 1. This data file contains 32 variables and 8,601 cases. This file contains UPC values on the packages of tobacco products used or in the possession of adult respondents at the time of Wave 1. The UPC values can be used to identify and validate the specific products used by respondents and augment the analyses of the characteristics of tobacco products used by these respondents at the time of Wave 1.

Dataset 1801 (DS1801) contains Location Characteristics for Wave 1 Adults. This data file contains 4 variables and 32,320 cases.

Dataset 1802 (DS1802) contains Location Characteristics for Wave 1 Youth. This data file contains 4 variables and 13,651 cases.

Dataset 1901 (DS1901) contains Study Research Derived Variables for Wave 1 Adults created by PATH Study analysts. This data file contains 104 variables and 32,320 cases.

Dataset 1902 (DS1902) contains Study Research Derived Variables for Wave 1 Youth created by PATH Study analysts. This data file contains 89 variables and 13,651 cases.

Dataset 2011 (DS2011) contains the data from the Wave 2 Adult Questionnaire. This data file contains 2,421 variables and 28,362 cases. Of these cases, 26,447 also completed a Wave 1 Adult Questionnaire. The other 1,915 cases are "aged-up adults" having previously completed a Wave 1 Youth Questionnaire.

Dataset 2012 (DS2012) contains the data from the Wave 2 Youth and Parent Questionnaire. This data file contains 1,596 variables and 12,172 cases. Of these cases, 10,081 also completed a Wave 1 Youth Questionnaire. The other 2,091 cases are "aged-up youth" having previously been sampled as "shadow youth."

Dataset 2411 (DS2411) contains the Wave 2 State Identifier data for Adults and has 5 variables and 28,362 cases. Dataset 2412 (DS2412) contains the Wave 2 State Identifier data for Youth and Parents and has 5 variables and 12,172 cases. The same 5 variables are in each State Identifier dataset, including PERSONID for linking the State Identifier to the questionnaire and biomarker data and 3 variables designating the state (state FIPS, state abbreviation, and full name of the state). The State Identifier values in these datasets represent participants' state of residence at the time of Wave 2.

Dataset 2611 (DS2611) contains the Tobacco Universal Product Code (UPC) data from Wave 2. This data file contains 32 variables and 7,295 cases. This file contains UPC values on the packages of tobacco products used or in the possession of adult respondents at the time of Wave 2. The UPC values can be used to identify and validate the specific products used by respondents and augment the analyses of the characteristics of tobacco products used by these respondents at the time of Wave 2.

Dataset 2801 (DS2801) contains Location Characteristics for Wave 2 Adults. This data file contains 4 variables and 28,362 cases.

Dataset 2802 (DS2802) contains Location Characteristics for Wave 2 Youth. This data file contains 4 variables and 12,172 cases.

Dataset 2901 (DS2901) contains Study Research Derived Variables for Wave 2 Adults created by PATH Study analysts. This data file contains 178 variables and 28,362 cases.

Dataset 2902 (DS2902) contains Study Research Derived Variables for Wave 2 Youth created by PATH Study analysts. This data file contains 123 variables and 12,172 cases.

Dataset 3011 (DS3011) contains the data from the Wave 3 Adult Questionnaire. This data file contains 2,359 variables and 28,148 cases. Of these cases, 26,241 are continuing adults having completed a prior Adult Questionnaire. The other 1,907 cases are "aged-up adults" having previously completed a Youth Questionnaire.

Dataset 3012 (DS3012) contains the data from the Wave 3 Youth and Parent Questionnaire. This data file contains 1,492 variables and 11,814 cases. Of these cases, 9,769 are continuing youth having completed a prior Youth Interview. The other 2,045 cases are "aged-up youth" having previously been sampled as "shadow youth."

Datasets 3111, 3211, 3112, and 3212 (DS3111, DS3211, DS3112, and DS3212) are data files comprising the weight variables for Wave 3. The weight variables for Wave 1 and Wave 2 are included in the main data files. However, starting with Wave 3, the weight variables have been separated into individual data files. The "all-waves" weight files contain weights for respondents who completed an interview for all waves in which they were old enough to do so or verified their information with the study for waves in which they were not old enough to be interviewed. The "single-wave" weight files contain weights for all respondents in Wave 3 regardless of their participation in previous waves.

Dataset 3503 (DS3503) contains data derived from responses to Wave 1-3 questionnaires indicating if participants had ever/never used various tobacco products as of the Wave 3 study period. This data file contains 25 variables for all 53,178 study participants as of Wave 3. This file is provided for reference only to simplify the definitions of tobacco use variables in the Adult and Youth data files for subsequent waves.

Dataset 3411 (DS3411) contains the Wave 3 State Identifier data for Adults and has 5 variables and 28,148 cases. Dataset 3412 (DS3412) contains the Wave 3 State Identifier data for Youth and Parents and has 5 variables and 11,814 cases. The same 5 variables are in each State Identifier dataset, including PERSONID for linking the State Identifier to the questionnaire and biomarker data and 3 variables designating the state (state FIPS, state abbreviation, and full name of the state). The State Identifier values in these datasets represent participants' state of residence at the time of Wave 3.

Dataset 3611 (DS3611) contains the Tobacco Universal Product Code (UPC) data from Wave 3. This data file contains 32 variables and 6,768 cases. This file contains UPC values on the packages of tobacco products used or in the possession of adult respondents at the time of Wave 3. The UPC values can be used to identify and validate the specific products used by respondents and augment the analyses of the characteristics of tobacco products used by these respondents at the time of Wave 3.

Dataset 3801 (DS3801) contains Location Characteristics for Wave 3 Adults. This data file contains 4 variables and 28,148 cases.

Dataset 3802 (DS3802) contains Location Characteristics for Wave 3 Youth. This data file contains 4 variables and 11,814 cases.

Dataset 3901 (DS3901) contains Study Research Derived Variables for Wave 3 Adults created by PATH Study analysts. This data file contains 107 variables and 28,148 cases.

Dataset 3902 (DS3902) contains Study Research Derived Variables for Wave 3 Youth created by PATH Study analysts. This data file contains 88 variables and 11,814 cases.

Dataset 4001 (DS4001) contains the data from the Wave 4 Adult Questionnaire. This data file contains 2,504 variables and 33,822 cases. Of these cases, 25,857 are continuing adults having completed a prior Adult Questionnaire, 1,900 are "aged-up adults" having previously completed a Youth Questionnaire, and 6,065 are "replenishment sample adults" (also known as "new cohort adults" in the annotated instrument).

Dataset 4002 (DS4002) contains the data from the Wave 4 Youth and Parent Questionnaire. This data file contains 1,600 variables and 14,798 cases. Of these cases, 9,365 are continuing youth having completed a prior Youth Interview, 1,694 cases are "aged-up youth" having previously been sampled as "shadow youth," and 3,739 are "replenishment sample youth" (also known as "new cohort youth" in the annotated instrument).

Datasets 4111, 4211, 4321, 4112, 4212, and 4322 (DS4111, DS4211, DS4321, DS4112, DS4212, and DS4322) are data files comprising the weight variables for Wave 4. In Wave 4, the weight variables have been separated into individual data files corresponding to the Wave 1 and Wave 4 Cohorts and different weight types. The "all-waves" weight files contain weights for those Wave 1 Cohort respondents who completed an interview for all waves in which they were old enough or verified their information for waves in which they were not old enough to be interviewed. The "single-wave" weight files contain weights for Wave 1 Cohort respondents at Wave 4 who completed an interview at Wave 1, regardless of their participation in previous waves. The "cross-sectional" weight files contain weights for all respondents in the Wave 4 Cohort.

Dataset 4401 (DS4401) contains the Wave 4 State Identifier data for Adults and has 5 variables and 33,822 cases. Dataset 4402 (DS4402) contains the Wave 4 State Identifier data for Youth and Parents and has 5 variables and 14,798 cases. The same 5 variables are in each State Identifier dataset, including PERSONID for linking the State Identifier to the questionnaire and biomarker data and 3 variables designating the state (state FIPS, state abbreviation, and full name of the state). The State Identifier values in these datasets represent participants' state of residence at the time of Wave 4. For adults and youth from the replenishment sample, the values also represent state of residence at the time of recruitment.

Dataset 4503 (DS4503) contains data derived from responses to Wave 1-4 questionnaires, indicating if participants had ever/never used various tobacco products as of the Wave 4 data collection period. This data file contains 27 variables for all 67,276 study participants as of the Wave 4 data collection. This file is provided for reference only to simplify the definitions of tobacco use variables in the Adult and Youth data files for subsequent waves.

Dataset 4601 (DS4601) contains the Tobacco Universal Product Code (UPC) data from Wave 4. This data file contains 32 variables and 7,684 cases. This file contains UPC values on the packages of tobacco products used or in the possession of adult respondents at the time of Wave 4. The UPC values can be used to identify and validate the specific products used by respondents and augment the analyses of the characteristics of tobacco products used by these respondents at the time of Wave 4.

Dataset 4801 (DS4801) contains Location Characteristics for Wave 4 Adults. This data file contains 4 variables and 33,822 cases.

Dataset 4802 (DS4802) contains Location Characteristics for Wave 4 Youth. This data file contains 4 variables and 14,798 cases.

Dataset 5001 (DS5001) contains the data from the Wave 5 Adult Questionnaire. This data file contains 2,606 variables and 34,309 cases. Of these cases, 29,876 are continuing adults having completed a prior Adult Questionnaire and 4,433 are "aged-up adults" having previously completed a Youth Questionnaire.

Dataset 5002 (DS5002) contains the data from the Wave 5 Youth and Parent Questionnaire. This data file contains 1,776 variables and 12,098 cases. Of these cases, 10,446 are continuing youth having completed a prior Youth Interview and 1,652 cases are "aged-up youth" having previously been sampled as "shadow youth."

Datasets 5111, 5112, 5211, 5212, 5221, 5222, 5711, 5712, 5721, and 5722 (DS5111, DS5112, DS5211, DS5212, DS5221, DS5222, DS5711, DS5712, DS5721, and DS5722) are data files comprising the weight variables for Wave 5. In Wave 5, the weight variables are in individual data files corresponding to the Wave 1 and Wave 4 Cohorts and different weight types. The "all-waves" weight files contain weights for those Wave 1 Cohort participants who completed a Wave 5 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, and 4.

There are two separate sets of files with "single wave" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "single-wave" weight files for the Wave 1 Cohort contain weights for participants who completed an interview in Wave 1 and in Wave 5, regardless of their participation in the intervening waves. The "single-wave" weight files for the Wave 4 Cohort contain weights for all Wave 5 interview respondents in the Wave 4 Cohort.

There are also two separate sets of files with "special collection all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "special collection all-waves" weight files for the Wave 1 Cohort contain weights for participants who completed a Wave 5 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, and the special collection in Wave 4.5. The "special collection all-waves" weight files for the Wave 4 Cohort contain weights for participants who completed a Wave 5 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Wave 4 and the special collection in Wave 4.5.

Dataset 5401 (DS5401) contains the Wave 5 State Identifier data for Adults and has 5 variables and 34,309 cases. Dataset 5402 (DS5402) contains the Wave 5 State Identifier data for Youth and Parents and has 5 variables and 12,098 cases. The same 5 variables are in each State Identifier dataset, including PERSONID for linking the State Identifier to the questionnaire and biomarker data and 3 variables designating the state (state FIPS, state abbreviation, and full name of the state). The State Identifier values in these datasets represent participants' state of residence at the time of Wave 5.

Dataset 5503 (DS5503) contains data derived from responses to Wave 1-5 (including Wave 4.5) questionnaires indicating if participants had ever/never used various tobacco products as of the Wave 5 data collection period. This data file contains 26 variables for all 67,276 study participants as of the Wave 5 data collection. This file is provided for reference only to simplify the definitions of tobacco use variables in the Adult and Youth data files for subsequent waves.

Dataset 5601 (DS5601) contains the Tobacco Universal Product Code (UPC) data from Wave 5. This data file contains 33 variables and 6,678 cases. This file contains UPC values on the packages of tobacco products used or in the possession of adult respondents at the time of Wave 5. The UPC values can be used to identify and validate the specific products used by respondents and augment the analyses of the characteristics of tobacco products used by these respondents at the time of Wave 5.

Dataset 5801 (DS5801) contains Location Characteristics for Wave 5 Adults. This data file contains 4 variables and 34,309 cases.

Dataset 5802 (DS5802) contains Location Characteristics for Wave 5 Youth. This data file contains 4 variables and 12,098 cases.

Dataset 6001 (DS6001) contains the data from the Wave 6 Adult Questionnaire. This data file contains 2,935 variables and 30,516 cases

Of these cases, 28,852 are continuing adults having completed a prior Adult Questionnaire and 1,664 are "aged-up adults" having previously completed a Youth Questionnaire.

Dataset 6002 (DS6002) contains the data from the Wave 6 Youth and Parent Questionnaire. This data file contains 2,080 variables and 5,652 cases. Of these cases, 5,622 are continuing youth having completed a prior Youth Interview and 60 cases are "aged-up youth" having previously been sampled as "shadow youth."

Datasets 6111, 6112, 6121, 6122, 6211, 6212, 6221, 6222, 6711, 6712, 6721, and 6722 (DS6111, DS6112, DS6121, DS6122, DS6211, DS6212, DS62221, DS6222, DS6711, DS6712, DS6721, and DS6722) are data files comprising the weight variables for Wave 6. In Wave 6, the weight variables are in individual data files corresponding to the Wave 1 and Wave 4 Cohorts and different weight types. There are two separate sets of files with "all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "all-waves" weight files for the Wave 1 Cohort contain weights for participants who completed a Wave 6 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, and 5. The "all-waves" weight files for the Wave 4 Cohort contain weights for participants who completed a Wave 6 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4 and 5.

There are two separate sets of files with "single-wave" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "single-wave" weight files for the Wave 1 Cohort contain weights for participants who completed an interview in Wave 1 and in Wave 6, regardless of their participation in the intervening waves. The "single-wave" weight files for the Wave 4 Cohort contain weights for participants who completed an interview in Wave 4 and in Wave 6, regardless of their participation in the intervening waves.

There are also two separate sets of files with "special collection all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "special collection all-waves" weight files for the Wave 1 Cohort contain weights for participants who completed a Wave 6 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, 5, and the special collections in Wave 4.5, and Wave 5.5 or PATH-ATS. The "special collection all-waves" weight files for the Wave 4 Cohort contain weights for participants who completed a Wave 6 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4 and 5, and the special collections in Wave 4.5, and Wave 5.5 or PATH-ATS.

Dataset 6401 (DS6401) contains the Wave 6 State Identifier data for Adults and has 5 variables and 30,516 cases. Dataset 6402 (DS6402) contains the Wave 6 State Identifier data for Youth and Parents and has 5 variables and 5,652 cases. The same 5 variables are in each State Identifier dataset, including PERSONID for linking the State Identifier to the questionnaire and biomarker data and 3 variables designating the state (state FIPS, state abbreviation, and full name of the state). The State Identifier values in these datasets represent participants' state of residence at the time of Wave 6.

Dataset 6503 (DS6503) contains data derived from responses to questionnaires in Waves 1-6 (including the special collections in Wave 4.5, Wave 5.5, and PATH-ATS) indicating if participants had ever/never used various tobacco products as of the Wave 6 data collection period. This data file contains 24 variables for all 67,276 study participants as of the Wave 6 data collection. This file is provided for reference only to simplify the definitions of tobacco use variables in the Adult and Youth data files for subsequent waves.

Dataset 6601 (DS6601) contains the Tobacco Universal Product Code (UPC) data from Wave 6. This data file contains 53 variables and 5,408 cases. This file contains UPC values on the packages of tobacco products used or in the possession of adult respondents at the time of Wave 6. The UPC values can be used to identify and validate the specific products used by respondents and augment the analyses of the characteristics of tobacco products used by these respondents at the time of Wave 6.

Dataset 6801 (DS6801) contains Location Characteristics for Wave 6 Adults. This data file contains 4 variables and 30,516 cases.

Dataset 6802 (DS6802) contains Location Characteristics for Wave 6 Youth. This data file contains 4 variables and 5,652 cases.

Dataset 7001 (DS7001) contains the data from the Wave 7 Adult Questionnaire. This data file contains 3,221 variables and 30,801 cases. Of these cases, 27,258 are continuing adults having completed a prior Adult Questionnaire, 1,740 are "aged-up adults" having previously completed a Youth Questionnaire, and 1,803 are "replenishment sample adults" (also known as "new cohort adults" in the annotated instrument).

Dataset 7002 (DS7002) contains the data from the Wave 7 Youth and Parent Questionnaire. This data file contains 2,171 variables and 10,834 cases. Of these cases, 3,512 are continuing youth having completed a prior Youth Interview, 1 case is an "aged-up youth" having previously been sampled as "shadow youth," and 7,321 are "replenishment sample youth" (also known as "new cohort youth" in the annotated instrument).

Datasets 7111, 7112, 7121, 7122, 7211, 7212, 7221, 7222, 7331, 7332, 7711, 7712, 7721, and 7722 (DS DS7111, DS7112, DS7121, DS7122, DS7211, DS7212, DS7221, DS7222, DS7331, DS7332, DS7711, DS7712, DS7721, and DS7722) are data files comprising the weight variables for Wave 7. In Wave 7, the weight variables are in individual data files corresponding to the Wave 1, Wave 4, and Wave 7 Cohorts and different weight types.

There are two separate sets of files with "all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "all-waves" weight files for the Wave 1 Cohort contain weights for participants who completed a Wave 7 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, 5, and 6. The "all-waves" weight files for the Wave 4 Cohort contain weights for participants who completed a Wave 7 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4, 5, and 6.

There are two separate sets of files with "single-wave" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "single-wave" weight files for the Wave 1 Cohort contain weights for participants who completed an interview in Wave 1 and in Wave 7, regardless of their participation in the intervening waves. The "single-wave" weight files for the Wave 4 Cohort contain weights for participants who completed an interview in Wave 4 and in Wave 7, regardless of their participation in the intervening waves.

There are also two separate sets of files with "special collection all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "special collection all-waves" weight files for the Wave 1 Cohort contain weights for participants who completed a Wave 7 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, 5, 6, and the special collections in Wave 4.5, and Wave 5.5 or PATH-ATS. The "special collection all-waves" weight files for the Wave 4 Cohort contain weights for participants who completed a Wave 7 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4, 5, 6, and the special collections in Wave 4.5, and Wave 5.5 or PATH-ATS.

The "cross-sectional" weight files contain weights for all respondents in the Wave 7 Cohort.

Dataset 7401 (DS7401) contains the Wave 7 State Identifier data for Adults and has 5 variables and 30,801 cases. Dataset 7402 (DS7402) contains the Wave 7 State Identifier data for Youth and Parents and has 5 variables and 10,834 cases. The same 5 variables are in each State Identifier dataset, including PERSONID for linking the State Identifier to the questionnaire and biomarker data and 3 variables designating the state (state FIPS, state abbreviation, and full name of the state). The State Identifier values in these datasets represent participants' state of residence at the time of Wave 7.

Dataset 7503 (DS7503) contains data derived from responses to questionnaires in Waves 1-7 (including the special collections in Wave 4.5, Wave 5.5, and PATH-ATS) indicating if participants had ever/never used various tobacco products as of the Wave 7 data collection period. This data file contains 26 variables for all 82,139 study participants as of the Wave 7 data collection. This file is provided for reference only to simplify the definitions of tobacco use variables in the Adult and Youth data files for subsequent waves.

Dataset 7601 (DS7601) contains the Tobacco Universal Product Code (UPC) data from Wave 7. This data file contains 53 variables and 4,533 cases. This file contains UPC values on the packages of tobacco products used or in the possession of adult respondents at the time of Wave 7. The UPC values can be used to identify and validate the specific products used by respondents and augment the analyses of the characteristics of tobacco products used by these respondents at the time of Wave 7.

Dataset 7801 (DS7801) contains Location Characteristics for Wave 7 Adults. This data file contains 4 variables and 30,801 cases.

Dataset 7802 (DS7802) contains Location Characteristics for Wave 7 Youth. This data file contains 4 variables and 10,834 cases.

Dataset 8001 (DS8001) contains the data from the Wave 8 Adult Questionnaire. This data file contains 3,467 variables and 31,477 cases. Of these cases, 30,021 are continuing adults having completed a prior Adult Questionnaire and 1,456 are "aged-up adults" having previously completed a Youth Questionnaire.

Dataset 8002 (DS8002) contains the data from the Wave 8 Youth and Parent Questionnaire. This data file contains 2,393 variables and 8,002 cases. Of these cases, 7,046 are continuing youth having completed a prior Youth Interview and 956 are "aged-up youth" having previously been sampled as "shadow youth."

Datasets 8111, 8121, 8122, 8211, 8221, 8231, 8232, 8711, 8721, 8722, 8731, and 8732 (DS8111, DS8121, DS8122, DS8211, DS8221, DS8231, DS8232, DS8711, 8DS721, DS8722, DS8731, and DS8732) are data files comprising the weight variables for Wave 8. In Wave 8, the weight variables are in individual data files corresponding to the Wave 1, Wave 4, and Wave 7 Cohorts and different weight types.

There are two separate sets of files with "all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "all-waves" weight files for the Wave 1 Cohort contain weights for participants who completed a Wave 8 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, 5, 6, and 7. Note that only adults have "all-waves" weights for the Wave 1 Cohort; youth from the Wave 1 Cohort aged-up to adults by the time of Wave 8. The "all-waves" weight files for the Wave 4 Cohort contain weights for participants who completed a Wave 8 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4, 5, 6, and 7.

There are three separate sets of files with "single-wave" weights: one for the Wave 1 Cohort, one for the Wave 4 Cohort, and one for the Wave 7 Cohort. The "single-wave" weight files for the Wave 1 Cohort contain weights for participants who completed an interview in Wave 1 and in Wave 8, regardless of their participation in the intervening waves. The "single-wave" weight files for the Wave 4 Cohort contain weights for participants who completed an interview in Wave 4 and in Wave 8, regardless of their participation in the intervening waves. Note that only adults have "single-wave" weights for the Wave 1 and Wave 4 Cohorts; youth from the Wave 1 Cohort aged-up to adults by the time of Wave 8 and youth from the Wave 4 Cohort were selected as shadow youth so they do not have any interview data from Wave 4. The "single wave" weights files for the Wave 7 Cohort contain weights for participants who completed an interview in Wave 7 and in Wave 8.

There are also three separate sets of files with "special collection all-waves" weights: one for the Wave 1 Cohort, one for the Wave 4 Cohort, and one for the Wave 7 Cohort. The "special collection all-waves" weight files for the Wave 1 Cohort contain weights for participants who completed a Wave 8 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, 5, 6, 7 and the special collections in Wave 4.5, Wave 5.5, and Wave 7.5. Note that only adults have "special collection all-waves" weights for the Wave 1 Cohort; youth from the Wave 1 Cohort aged-up to adults by the time of Wave 8. The "special collection all-waves" weight files for the Wave 4 Cohort contain weights for participants who completed a Wave 8 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4, 5, 6, 7, and the special collections in Wave 4.5, Wave 5.5, and Wave 7.5. The "special collection all-waves" weight files for the Wave 7 Cohort contain weights for participants who completed a Wave 8 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Wave 7 and the special collection in Wave 7.5.

Dataset 8401 (DS8401) contains the Wave 8 State Identifier data for Adults and has 5 variables and 31,477 cases. Dataset 8402 (DS8402) contains the Wave 8 State Identifier data for Youth and Parents and has 5 variables and 8,002 cases. The same 5 variables are in each State Identifier dataset, including PERSONID for linking the State Identifier to the questionnaire and biomarker data and 3 variables designating the state (state FIPS, state abbreviation, and full name of the state). The State Identifier values in these datasets represent participants' state of residence at the time of Wave 8.

Dataset 8801 (DS8801) contains Location Characteristics for Wave 8 Adults. This data file contains 4 variables and 31,477 cases.

Dataset 8802 (DS8802) contains Location Characteristics for Wave 8 Youth. This data file contains 4 variables and 8,002 cases.

Each case in an Adult data file represents a single, completed interview. Each case in a Youth data file represents one youth and his or her parent's responses about that youth. Parents who provided permission for their child to participate in a Youth Interview were asked to complete a brief interview about their child. In all waves of data collection, less than 0.5 percent of the parents did not complete an interview. Most questions are asked about the child.

When multiple youth from the same household were selected to be in the study, the parent(s) completed separate interviews about each youth. If one parent completed two or more interviews, that parent only answered questions about himself/herself once. Those questions were then skipped in the subsequent interview(s) for the other child(ren) and the responses duplicated in that child(ren)'s data file(s).

The PATH Study was launched in 2011 to inform the Food and Drug Administration's regulatory activities under the Family Smoking Prevention and Tobacco Control Act (TCA). The PATH Study is a collaboration between the National Institute on Drug Abuse (NIDA), National Institutes of Health (NIH), and the Center for Tobacco Products (CTP), Food and Drug Administration (FDA). The study sampled over 150,000 mailing addresses across the United States to create a national sample of people who do and do not use tobacco.

45,971 adults and youth constitute the first (baseline) wave, Wave 1, of data collected by this longitudinal cohort study. These 45,971 adults and youth along with 7,207 "shadow youth" (youth ages 9 to 11 sampled at Wave 1) make up the 53,178 participants that constitute the Wave 1 Cohort. Respondents are asked to complete an interview at each follow-up wave. Youth who turn 18 by the current wave of data collection are considered "aged-up adults" and are invited to complete the Adult Interview. Additionally, "shadow youth" are considered "aged-up youth" upon turning 12 years old, when they are asked to complete an interview after parental consent.

At Wave 4, a probability sample of 14,098 adults, youth, and shadow youth ages 10 to 11 was selected from the civilian, noninstitutionalized population (CNP) at the time of Wave 4. This sample was recruited from residential addresses not selected for Wave 1 in the same sampled Primary Sampling Units (PSUs) and segments using similar within-household sampling procedures. This "replenishment sample" was combined for estimation and analysis purposes with Wave 4 adult and youth respondents from the Wave 1 Cohort who were in the CNP at the time of Wave 4. This combined set of Wave 4 participants, 52,731 participants in total, forms the Wave 4 Cohort.

At Wave 7, a probability sample of 14,863 adults, youth, and shadow youth ages 9 to 11 was selected from the CNP at the time of Wave 7. This sample was recruited from residential addresses not selected for Wave 1 or Wave 4 in the same sampled PSUs and segments using similar within-household sampling procedures. This "second replenishment sample" was combined for estimation and analysis purposes with the Wave 7 adult and youth respondents from the Wave 4 Cohorts who were at least age 15 and in the CNP at the time of Wave 7. This combined set of Wave 7 participants, 46,169 participants in total, forms the Wave 7 Cohort.

Please refer to the Public-Use Files User Guide that provides further details about children designated as "shadow youth" and the formation of the Wave 1, Wave 4, and Wave 7 Cohorts.

Wave 4.5 was a special data collection for youth only who were aged 12 to 17 at the time of the Wave 4.5 interview. Wave 4.5 was the fourth annual follow-up wave for those who were members of the Wave 1 Cohort. For those who were sampled at Wave 4, Wave 4.5 was the first annual follow-up wave.

Wave 5.5, conducted in 2020, was a special data collection for Wave 4 Cohort youth and young adults ages 13 to 19 at the time of the Wave 5.5 interview. Also in 2020, a subsample of Wave 4 Cohort adults ages 20 and older were interviewed via the PATH Study Adult Telephone Survey (PATH-ATS).

Wave 7.5 was a special collection for Wave 4 and Wave 7 Cohort youth and young adults ages 12 to 22 at the time of the Wave 7.5 interview. For those who were sampled at Wave 7, Wave 7.5 was the first annual follow-up wave.

Dataset 1002 (DS1002) contains the data from the Wave 4.5 Youth and Parent Questionnaire. This file contains 1,395 variables and 13,131 cases. Of these cases, 11,378 are continuing youth having completed a prior Youth Interview. The other 1,753 cases are "aged-up youth" having previously been sampled as "shadow youth."

Datasets 1112, 1212, and 1222, (DS1112, DS1212, and DS1222) are data files comprising the weight variables for Wave 4.5. The "all-waves" weight file contains weights for participants in the Wave 1 Cohort who completed a Wave 4.5 Youth Interview and completed interviews (if old enough to do so) or verified their information with the study (if not old enough to be interviewed) in Waves 1, 2, 3, and 4.

There are two separate files with "single wave" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "single-wave" weight file for the Wave 1 Cohort contains weights for youth who completed an interview in Wave 1 and in Wave 4.5, regardless of their participation in the intervening waves. The "single-wave" weight file for the Wave 4 Cohort contains weights for all Wave 4.5 Youth Interview respondents in the Wave 4 Cohort.

Dataset 1503 (DS1503) contains data derived from responses to questionnaires in Wave 1, Wave 2, Wave 3, Wave 4, and Wave 4.5 indicating if participants had ever/never used various tobacco products as of the Wave 4.5 data collection period. This data file contains 26 variables for all 67,276 study participants as of the Wave 4.5 data collection. This file is provided for reference only to simplify the definitions of tobacco use variables in the Adult and Youth data files for subsequent waves.

Dataset 2001 (DS2001) contains the data from the Wave 5.5 Adult Questionnaire. This file contains 2,323 variables and 3,628 cases. Of these cases, 1,014 are continuing adults having completed a prior Adult Questionnaire. The other 2,614 cases are "aged-up adults" having previously completed a Youth Questionnaire.

Dataset 2002 (DS2002) contains the data from the Wave 5.5 Youth and Parent Questionnaire. This file contains 1,625 variables and 7,129 cases. Of these cases, 7,076 are continuing youth having completed a prior Youth Interview. The other 53 cases are "aged-up youth" having previously been sampled as "shadow youth."

Datasets 2111, 2112, 2121, 2122, 2221, and 2222 (DS2111, DS2112, DS2121, DS2122, DS2221, and DS2222) are data files comprising the weight variables for Wave 5.5. In Wave 5.5, the weight variables are in individual data files corresponding to the Wave 1 and Wave 4 Cohorts and different weight types.

There are two separate sets of files with "all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "all-waves" weight file for the Wave 1 Cohort contains weights for participants who completed a Wave 5.5 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, 4.5, and 5. The "all-waves" weight file for the Wave 4 Cohort contains weights for participants who completed a Wave 5.5 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4, 4.5, and 5.

The "single-wave" weight file for the Wave 4 Cohort contains weights for all Wave 5.5 interview respondents.

Dataset 3001 (DS3001) contains the data from PATH-ATS. This file contains 908 variables and 8,874 cases, all of which are continuing adults having completed a prior Adult Questionnaire, with their most recent interview in Wave 5.

Datasets 3111 and 3121 (DS3111 and DS3121) are data files comprising weights for PATH-ATS. In PATH-ATS, weight variables are in individual files corresponding to the Wave 1 and Wave 4 Cohorts.

The "all-waves" weight file for the Wave 1 Cohort contains weights for participants who completed an interview in PATH-ATS and completed interviews in Waves 1, 2, 3, 4, and 5. The "all-waves" weight file for the Wave 4 Cohort contains weights for participants who completed an interview in PATH-ATS; all PATH-ATS respondents completed interviews in Wave 4 and Wave 5.

Dataset 2503 (DS2503) contains data derived from responses to questionnaires in Wave 1, Wave 2, Wave 3, Wave 4, Wave 4.5, Wave 5, Wave 5.5, and PATH-ATS, indicating if participants had ever/never used various tobacco products as of the Wave 5.5/PATH-ATS data collection period. This data file contains 26 variables for all 67,276 study participants as of the Wave 5.5/PATH-ATS data collection. This file is provided for reference only to simplify the definitions of tobacco use variables in the Adult and Youth data files for subsequent waves.

Dataset 4001 (DS4001) contains the data from the Wave 7.5 Adult Questionnaire. This file contains 2,760 variables and 7,961 cases. Of these cases, 5,952 are continuing adults having completed a prior Adult Questionnaire. The other 2,009 cases are "aged-up adults" having previously completed a Youth Questionnaire.

Dataset 4002 (DS4002) contains the data from the Wave 7.5 Youth and Parent Questionnaire. This file contains 1,889 variables and 8,949 cases. Of these cases, 7,064 are continuing youth having completed a prior Youth Interview. The other 1,885 cases are "aged-up youth" having previously been sampled as "shadow youth."

Datasets 4111, 4112, 4121, 4122, 4221, 4222, 4231, and 4232 (DS4111, DS4112, DS4121, DS4122, DS4221, DS4222, DS4231, and DS4232) are data files comprising the weight variables for Wave 7.5. In Wave 7.5, the weight variables are in individual data files corresponding to the Wave 1, Wave 4, and Wave 7 Cohorts and different weight types.

There are two separate sets of files with "all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "all-waves" weight file for the Wave 1 Cohort contains weights for participants who completed a Wave 7.5 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, 4.5, 5, 5.5, 6, and 7. The "all-waves" weight file for the Wave 4 Cohort contains weights for participants who completed a Wave 7.5 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4, 4.5, 5, 5.5, 6, and 7.

There are two separate sets of files with "single-waves" weights: one for the Wave 4 Cohort and one for the Wave 7 Cohort. The "single-wave" weight file for the Wave 4 Cohort contains weights for Wave 7.5 interview respondents in the Wave 4 Cohort, regardless of their response status at Waves 4.5, 5, 5.5, 6, or 7. The "single-wave" weight file for the Wave 7 Cohort contains weights for all Wave 7.5 interview respondents in the Wave 7 Cohort.

Dataset 4503 (DS4503) contains data derived from responses to questionnaires in Wave 1, Wave 2, Wave 3, Wave 4, Wave 4.5, Wave 5, Wave 5.5, PATH-ATS, Wave 6, Wave 7, and Wave 7.5, indicating if participants had ever/never used various tobacco products as of the Wave 7.5 data collection period. This data file contains 25 variables for all 82,139 study participants as of the Wave 7.5 data collection. This file is provided for reference only to simplify the definitions of tobacco use variables in the Adult and Youth data files for subsequent waves.

The PATH Study was launched in 2011 to inform the Food and Drug Administration's regulatory activities under the Family Smoking Prevention and Tobacco Control Act (TCA). The PATH Study is a collaboration between the National Institute on Drug Abuse (NIDA), National Institutes of Health (NIH), and the Center for Tobacco Products (CTP), Food and Drug Administration (FDA). The study sampled over 150,000 mailing addresses across the United States to create a national sample of people who use or do not use tobacco.

45,971 adults and youth constitute the first (baseline) wave, Wave 1, of data collected by this longitudinal cohort study. These 45,971 adults and youth along with 7,207 "shadow youth" (youth ages 9 to 11 sampled at Wave 1) make up the 53,178 participants that constitute the Wave 1 Cohort. Respondents are asked to complete an interview at each follow-up wave. Youth who turn 18 by the current wave of data collection are considered "aged-up adults" and are invited to complete the Adult Interview. Additionally, "shadow youth" are considered "aged-up youth" upon turning 12 years old, when they are asked to complete an interview after parental consent.

At Wave 4, a probability sample of 14,098 adults, youth, and shadow youth ages 10 to 11 was selected from the civilian, noninstitutionalized population (CNP) at the time of Wave 4. This sample was recruited from residential addresses not selected for Wave 1 in the same sampled Primary Sampling Units (PSUs) and segments using similar within-household sampling procedures. This "replenishment sample" was combined for estimation and analysis purposes with Wave 4 adult and youth respondents from the Wave 1 Cohort who were in the CNP at the time of Wave 4. This combined set of Wave 4 participants, 52,731 participants in total, forms the Wave 4 Cohort.

At Wave 7, a probability sample of 14,863 adults, youth, and shadow youth ages 9 to 11 was selected from the CNP at the time of Wave 7. This sample was recruited from residential addresses not selected for Wave 1 or Wave 4 in the same sampled PSUs and segments using similar within-household sampling procedures. This "second replenishment sample" was combined for estimation and analysis purposes with the Wave 7 adult and youth respondents from the Wave 4 Cohorts who were at least age 15 and in the CNP at the time of Wave 7. This combined set of Wave 7 participants, 46,169 participants in total, forms the Wave 7 Cohort.

Please refer to the Restricted-Use Files User Guide that provides further details about children designated as "shadow youth" and the formation of the Wave 1, Wave 4, and Wave 7 Cohorts.

Wave 4.5 was a special data collection for youth only who were aged 12 to 17 at the time of the Wave 4.5 interview. Wave 4.5 was the fourth annual follow-up wave for those who were members of the Wave 1 Cohort. For those who were sampled at Wave 4, Wave 4.5 was the first annual follow-up wave.

Wave 5.5, conducted in 2020, was a special data collection for Wave 4 Cohort youth and young adults ages 13 to 19 at the time of the Wave 5.5 interview. Also in 2020, a subsample of Wave 4 Cohort adults ages 20 and older were interviewed via the PATH Study Adult Telephone Survey (PATH-ATS).

Wave 7.5 was a special collection for Wave 4 and Wave 7 Cohort youth and young adults ages 12 to 22 at the time of the Wave 7.5 interview. For those who were sampled at Wave 7, Wave 7.5 was the first annual follow-up wave.

Dataset 1002 (DS1002) contains the data from the Wave 4.5 Youth and Parent Questionnaire. This file contains 1,617 variables and 13,131 cases. Of these cases, 11,378 are continuing youth having completed a prior Youth Interview. The other 1,753 cases are "aged-up youth" having previously been sampled as "shadow youth"

Datasets 1112, 1212, and 1222, (DS1112, DS1212, and DS1222) are data files comprising the weight variables for Wave 4.5. The "all-waves" weight file contains weights for participants in the Wave 1 Cohort who completed a Wave 4.5 Youth Interview and completed interviews (if old enough to do so) or verified their information with the study (if not old enough to be interviewed) in Waves 1, 2, 3, and 4.

There are two separate files with "single wave" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "single-wave" weight file for the Wave 1 Cohort contains weights for youth who completed an interview in Wave 1 and in Wave 4.5, regardless of their participation in the intervening waves. The "single-wave" weight file for the Wave 4 Cohort contains weights for all Wave 4.5 Youth Interview respondents in the Wave 4 Cohort.

Dataset 1402 (DS1402) contains the Wave 4.5 State Identifier data for Youth and Parents and has 5 variables and 13,131 cases. The State Identifier dataset includes PERSONID for linking the State Identifier to the questionnaire data and 3 variables designating the state (state Federal Information Processing System (FIPS), state abbreviation, and full name of the state). The State Identifier values in this dataset represent participants' state of residence at the time of Wave 4.5.

Dataset 1503 (DS1503) contains data derived from responses to questionnaires in Wave 1, Wave 2, Wave 3, Wave 4, and Wave 4.5 indicating if participants had ever/never used various tobacco products as of the Wave 4.5 data collection period. This data file contains 26 variables for all 67,276 study participants as of the Wave 4.5 data collection. This file is provided for reference only to simplify the definitions of tobacco use variables in the Adult and Youth data files for subsequent waves.

Dataset 2001 (DS2001) contains the data from the Wave 5.5 Adult Questionnaire. This file contains 2,619 variables and 3,628 cases. Of these cases, 1,014 are continuing adults having completed a prior Adult Questionnaire. The other 2,614 cases are "aged-up adults" having previously completed a Youth Questionnaire.

Dataset 2002 (DS2002) contains the data from the Wave 5.5 Youth and Parent Questionnaire. This file contains 1,871 variables and 7,129 cases. Of these cases, 7,076 are continuing youth having completed a prior Youth Interview. The other 53 cases are "aged-up youth" having previously been sampled as "shadow youth."

Datasets 2111, 2112, 2121, 2122, 2221, and 2222 (DS2111, DS2112, DS2121, DS2122, DS2221, and DS2222) are data files comprising the weight variables for Wave 5.5. In Wave 5.5, the weight variables are in individual data files corresponding to the Wave 1 and Wave 4 Cohorts and different weight types.

There are two separate sets of files with "all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "all-waves" weight file for the Wave 1 Cohort contains weights for participants who completed a Wave 5.5 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, 4.5, and 5. The "all-waves" weight file for the Wave 4 Cohort contains weights for participants who completed a Wave 5.5 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4, 4.5 and 5.

The "single-wave" weight file for the Wave 4 Cohort contains weights for all Wave 5.5 interview respondents.

Dataset 2401 (DS2401) contains the Wave 5.5 State Identifier data for Adults and has 5 variables and 3,628 cases. Dataset 2402 (DS2402) contains the Wave 5.5 State Identifier data for Youth and Parents and has 5 variables and 7,129 cases. The same 5.5 variables are in each State Identifier dataset, including PERSONID for linking the State Identifier to the questionnaire and biomarker data and 3 variables designating the state (state FIPS, state abbreviation, and full name of the state). The State Identifier values in these datasets represent participants' state of residence at the time of Wave 5.5.

Dataset 2503 (DS2503) contains data derived from responses to questionnaires in Wave 1, Wave 2, Wave 3, Wave 4, Wave 4.5, Wave 5, and Wave 5.5 indicating if participants had ever/never used various tobacco products as of the Wave 5.5 data collection period. This data file contains 26 variables for all 67,276 study participants as of the Wave 5.5 data collection. This file is provided for reference only to simplify the definitions of tobacco use variables in the Adult and Youth data files for subsequent waves.

Dataset 3001 (DS3001) contains the data from PATH-ATS. This file contains 977 variables and 8,874 cases, all of which are continuing adults having completed a prior Adult Questionnaire, with their most recent interview in Wave 5.

Datasets 3111 and 3121 (DS3111 and DS3121) are data files comprising weights for PATH-ATS. In PATH-ATS, weight variables are in individual files corresponding to the Wave 1 and Wave 4 Cohorts.

The "all-waves" weight file for the Wave 1 Cohort contains weights for participants who completed an interview in PATH_-ATS and completed interviews in Waves 1, 2, 3, 4, and 5. The "all-waves" weight file for the Wave 4 Cohort contains weights for participants who completed an interview in PATH-ATS; all PATH-ATS respondents completed interviews in Wave 4 and Wave 5.

Dataset 3401 (DS3401) contains the PATH-ATS State Identifier data and has 5 variables and 8,874 cases. The State Identifier dataset includes PERSONID for linking the State Identifier to the questionnaire and biomarker data and 3 variables designating the state (state FIPS, state abbreviation, and full name of the state). The State Identifier values in this dataset represents participants' state of residence at the time of PATH-ATS.

Dataset 4001 (DS4001) contains the data from the Wave 7.5 Adult Questionnaire. This file contains 3,142 variables and 7,961 cases. Of these cases, 5,952 are continuing adults having completed a prior Adult Questionnaire. The other 2,009 cases are "aged-up adults" having previously completed a Youth Questionnaire.

Dataset 4002 (DS4002) contains the data from the Wave 7.5 Youth and Parent Questionnaire. This file contains 2,169 variables and 8,949 cases. Of these cases, 7,064 are continuing youth having completed a prior Youth Interview. The other 1,885 cases are "aged-up youth" having previously been sampled as "shadow youth."

Datasets 4111, 4112, 4121, 4122, 4221, 4222, 4231, and 4232 (DS4111, DS4112, DS4121, DS4122, DS4221, DS4222, DS4231, and DS4232) are data files comprising the weight variables for Wave 7.5. In Wave 7.5, the weight variables are in individual data files corresponding to the Wave 1, Wave 4, and Wave 7 Cohorts and different weight types.

There are two separate sets of files with "all-waves" weights: one for the Wave 1 Cohort and one for the Wave 4 Cohort. The "all-waves" weight file for the Wave 1 Cohort contains weights for participants who completed a Wave 7.5 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 1, 2, 3, 4, 4.5, 5, 5.5, 6, and 7. The "all-waves" weight file for the Wave 4 Cohort contains weights for participants who completed a Wave 7.5 interview and completed interviews (if old enough to do so) or verified their information (if not old enough to be interviewed) in Waves 4, 4.5, 5, 5.5, 6, and 7.

There are two separate sets of files with "single-waves" weights: one for the Wave 4 Cohort and one for the Wave 7 Cohort. The "single-wave" weight file for the Wave 4 Cohort contains weights for Wave 7.5 interview respondents in the Wave 4 Cohort, regardless of their response status at Waves 4.5, 5, 5.5, 6, or 7. The "single-wave" weight file for the Wave 7 Cohort contains weights for all Wave 7.5 interview respondents in the Wave 7 Cohort.

Dataset 4401 (DS4401) contains the Wave 7.5 State Identifier data for Adults and has 5 variables and 7,961 cases. Dataset 4402 (DS4402) contains the Wave 7.5 State Identifier data for Youth and Parents and has 5 variables and 8,949 cases. The same 7.5 variables are in each State Identifier dataset, including PERSONID for linking the State Identifier to the questionnaire and biomarker data and 3 variables designating the state (state FIPS, state abbreviation, and full name of the state). The State Identifier values in these datasets represent participants' state of residence at the time of Wave 7.5.

Dataset 4503 (DS4503) contains data derived from responses to questionnaires in Wave 1, Wave 2, Wave 3, Wave 4, Wave 4.5, Wave 5, Wave 5.5, PATH-ATS, Wave 6, Wave 7, and Wave 7.5 indicating if participants had ever/never used various tobacco products as of the Wave 7.5 data collection period. This data file contains 25 variables for all 82,139 study participants as of the Wave 7.5 data collection. This file is provided for reference only to simplify the definitions of tobacco use variables in the Adult and Youth data files for subsequent waves.

Dataset 4601 (DS4601) contains the Tobacco Universal Product Code (UPC) data from Wave 7.5. This data file contains 53 variables and 157 cases. This file contains UPC values on the packages of tobacco products used or in the possession of adult respondents at the time of Wave 7.5. The UPC values can be used to identify and validate the specific products used by respondents and augment the analyses of the characteristics of tobacco products used by these respondents at the time of Wave 7.5.

The Schools and Families Education (SAFE) Children Study was a randomized control trial designed to test the efficacy of a family-based comprehensive preventive intervention, with children living in inner-city Chicago and entering the 1st grade, for effects on key risk markers for later drug and other substance use.

A total of 11 waves of data were collected over the course of three phases and approximately 13 years. In the spring of 1997, there were 424 kindergarten students and primary caregivers recruited to participate in this study. Wave 1 began while the children were in 1st grade. These data contain survey responses for students, their primary caregivers, and their teachers across 27 datasets.

Phase I of the study was to assess the intervention provided in the 1st grade. Half of the families were randomly selected to receive the intervention. The other half were assigned to the control group. Phase II of the study was set-up to give half of the intervention group a booster, a second intervention training. Lastly, there was a Phase III which sought to assess the long-term affects of the initial and booster interventions.

The first dataset (DS1) provides an overview of the study which includes variables for the study design and survey administration. This first file contains 38 variables.

Survey responses were obtained from students nine times beginning in 1st grade and ending in 12th grade. Children were not surveyed in waves 3 and 7. The student survey response data are in DS2 through DS10. The datasets for waves 1, 2, 4, and 5 contain only 50 variables. Waves 6, 8, and 9 contain 424 variables. Waves 10 and 11 contain 1,394 variables. Each of the three phases contain almost identical variables within their respective waves.

The children's primary caregivers were also surveyed nine times over the survey period. Primary caregivers were not surveyed in waves 3 and 7. These data are contained in DS11 through DS19. The primary caregiver files vary in the number and content of variables. On average each wave contains about 1,060 variables with a low of 470 on up to a high of 1,435.

Teachers were surveyed during each of the first eight waves of the study. The teacher data are in DS20 through DS27. Waves 1 and 2 contain just over 120 variables. Waves 3, 4, and 5 contain 145 variables. And waves 6, 7, and 8 contain 173 variables. Each of the three phases contain almost identical variables within their respective waves.