Drug Abuse Treatment Outcome Study (DATOS), 1991-1994: [United States] (ICPSR 2258)

Version Date: Feb 16, 2010 View help for published

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United States Department of Health and Human Services. National Institutes of Health. National Institute on Drug Abuse


Version V5

DATOS, 1991-1994

Drug-Abuse Treatment Outcomes Study (DATOS) is a prospective study designed to determine the outcomes of adult drug abuse treatment delivered in typical, stable, community-based programs and to provide comprehensive information on continuing and new questions about the effectiveness of drug abuse treatment for adults currently available in a variety of publicly funded and private programs. The study examined the role of treatment outcomes and program type, client characteristics (including dependence, treatment history, and physical and mental health comorbidities), treatment received (e.g., length and intensity of services provided), therapeutic approaches, provision of aftercare, and research on the components of effective treatment, including factors that engage and retain clients in programs. Four types of programs were included: outpatient methadone (OPM), short-term inpatient (STI), long-term residential (LTR), and outpatient drug-free (ODF). Respondents were sampled from among adults admitted to drug abuse treatment programs in 11 representative U.S. cities during 1991-1993.

Clients entering treatment completed two comprehensive intake interviews (Intake 1 and Intake 2), approximately one week apart. This information is provided in Parts 1 and 2 of the data collection. These interviews were designed to obtain baseline data on drug use and other behaviors, as well as information on background and demographic characteristics, patterns of dependence, living situation and child custody status, education and training, income and expenditures, and HIV risk behaviors, along with assessments of dependence, mental health, physical health, and social functioning. Data on criminal justice status and criminal behavior are reported in Part 5, Illegal Activities Data, and are drawn from the Intake 1 interview. Data reflecting during-treatment progress, including service delivery and client satisfaction, were collected in the one-, three-, and six-month in-treatment interviews (Parts 3, 4, and 8). The 12-Month Post-Treatment Follow-Up Interview (Part 6) replicated many of the intake questions and focused on key behaviors in the year following treatment. Part 7 includes variables for time in treatment and interview availability indicators. The 12-Month Follow-Up Urine Result data (Part 9) provide the results from urine sample tests that were given to a sample of subjects at the time of the 12-Month Follow-Up Interview. Urine specimens were tested for eight categories of drugs (amphetamines, barbiturates, benzodiazepines, cannabinoids, cocaine metabolite, methaqualone, opiates, and phencyclidine). The drugs covered in the study were alcohol, tobacco, marijuana (hashish, THC), hallucinogens or psychedelics such as LSD, mescaline, and PCP, cocaine (including crack), heroin, narcotics or opiates such as morphine, codeine, Demerol, Dilaudid, and Talwin, downers or depressants such as sedatives, barbiturates, and tranquilizers, amphetamines or other stimulants such as speed or diet pills, and other drugs. Part 10 contains data for 1393 clients who were interviewed 5 years post treatment. This part contains many of the same types of questions asked during previous interviews.

United States Department of Health and Human Services. National Institutes of Health. National Institute on Drug Abuse. Drug Abuse Treatment Outcome Study (DATOS), 1991-1994: [United States]. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2010-02-16. https://doi.org/10.3886/ICPSR02258.v5

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United States Department of Health and Human Services. National Institutes of Health. National Institute on Drug Abuse (U01-DA10377-3, 271-89-8233, N01DA-9-8233)

Users are reminded by the National Institute on Drug Abuse (NIDA) that these data are to be used solely for statistical analysis and reporting of aggregated information and not for the investigation of specific individuals or organizations.

Inter-university Consortium for Political and Social Research
1991 -- 1999
1991 -- 1999

Users are advised that the data are most appropriately analyzed by modality.

The Intake 1 and Intake 2 data files contain several continuous variables that denote age at the time of a certain event. For some of these variables, dichotomous codes 1 and 95 were also used for "don't know but under 15" and "don't know but 15 or older," respectively. Code 1 was also used for actual responses of "1 year old." Because it is unlikely that these events occurred at age 1, the code 1 was changed to 94 ("1 or don't know but under 15") in order to make it clearer that this code denotes something other than age 1. Users are cautioned that this may have an effect on any analyses performed using these variables.

DATOS is an ongoing collaborative research effort of the National Development and Research Institutes at North Carolina (NDRI), Texas Christian University, the University of California at Los Angeles, and NIDA. For additional information, see the DATOS Web site.

A total of 96 treatment programs in 11 mid-size and large United States cities with well-established treatment systems participated in DATOS. Programs were purposively sampled to reflect typical clinical approaches across the four modalities: outpatient methadone, short-term inpatient, long-term residential, and outpatient drug-free. Geographic location, type of program, and representativeness of the program and its clients were considered in the three-level process of selecting cities, programs, and clients. Respondents were sampled from among those admitted to treatment in sampled facilities in 1991-1993. A total of 10,010 clients participated in the Intake 1 interview. Of those, 8,755 participated in the Intake 2 interview, 6,148 in the one-month intreatment interview, 3,180 in the three-month intreatment interview, and 2,966 in the 12-month follow-up. The sample for Intake 1 was 66 percent male, 47 percent African American, and 13 percent Hispanic, with a mean age of 33 years. However, these and other client characteristics varied across modalities, reflecting differing therapeutic and operational characteristics. For the 12-month follow-up sample, 4,229 of the eligible clients who completed the two-stage intake interviews were selected for follow-up using a stratified random design. Of these respondents, 74 percent (n = 3,147) were located, 70 percent (n = 2,966) were successfully interviewed, 1.5 percent (n = 64) were deceased, and 2.7 percent (n = 117) refused to participate. Gender, ethnicity, and average age were not significantly different between the intake and follow-up samples. A random 25 percent of the follow-up sample was selected for urine testing. Altogether, 770 of the respondents interviewed at follow-up were selected for urine testing. From this group, 621 urine samples were obtained. The remaining cases included refusals and situations in which it was impossible to obtain a urine sample. Altogether, 21 percent of the follow-up respondents had urine drug screening results.

Clients admitted to selected drug treatment programs in 1991-1993.

clinical data, survey data


2018-02-15 The citation of this study may have changed due to the new version control system that has been implemented. The previous citation was:
  • United States Department of Health and Human Services. National Institutes of Health. National Institute on Drug Abuse. Drug Abuse Treatment Outcome Study (DATOS), 1991-1994: [United States]. ICPSR02258-v5. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2010-02-16. http://doi.org/10.3886/ICPSR02258.v5

2010-02-16 A new part (#10) was added to the data files. It is a 5 year post treatment follow-up.

2007-11-28 The question text was updated to enhance the clarity of each question by adding in question stems and qualifying information. Also, minor typographical errors were corrected.

2007-02-19 SAS transport (XPORT), SPSS portable, and Stata system files were added to Parts 1-4, 6, and 8. Some corrections were made to the codebooks.

2005-11-04 On 2005-03-14 new files were added to one or more datasets. These files included additional setup files as well as one or more of the following: SAS program, SAS transport, SPSS portable, and Stata system files. The metadata record was revised 2005-11-04 to reflect these additions.

2004-07-01 Three datasets were added to the study: Time in Treatment and Interview Availability Indicators (Part 7), 6-Month Intreatment Interview Data (Part 8), and 12-Month Follow-Up Urine Result Data (Part 9). Corresponding documentation was prepared for each.

2000-05-01 ICPSR data undergo a confidentiality review and are altered when necessary to limit the risk of disclosure. ICPSR also routinely creates ready-to-go data files along with setups in the major statistical software formats as well as standard codebooks to accompany the data. In addition to these procedures, ICPSR performed the following processing steps for this data collection:

  • Performed consistency checks.
  • Created variable labels and/or value labels.
  • Standardized missing values.
  • Created online analysis version with question text.
  • Performed recodes and/or calculated derived variables.
  • Checked for undocumented or out-of-range codes.


  • The public-use data files in this collection are available for access by the general public. Access does not require affiliation with an ICPSR member institution.

  • The citation of this study may have changed due to the new version control system that has been implemented. Please see version history for more details.

This study is maintained and distributed by the National Addiction & HIV Data Archive Program (NAHDAP). NAHDAP is supported by the National Institute on Drug Abuse (NIDA), part of the National Institutes of Health (NIH).