National Archive of Computerized Data on Aging

This study is maintained and distributed by the National Archive of Computerized Data on Aging (NACDA), the aging program within ICPSR. NACDA is sponsored by the National Institute on Aging (NIA) at the National Institutes of Heath (NIH).

Midlife in the United States (MIDUS 2): Cognitive Project, 2004-2006 (ICPSR 25281)

Principal Investigator(s): Ryff, Carol D., University of Wisconsin-Madison; Lachman, Margie E., Brandeis University


In 1994/1995, the MacArthur Midlife Research Network carried out a national survey of over 7,000 Americans aged 25 to 74. The purpose of the study was to investigate the role of behavioral, psychological, and social factors in understanding age-related differences in physical and mental health. A description of the study and findings from it are available at With support from the National Institute on Aging, a longitudinal follow-up of the original MIDUS samples (core sample (N = 3,487), metropolitan over-samples (N = 757), twins (N = 957 pairs), and siblings (N = 950)) was conducted in 2004-2006. Guiding hypotheses, at the most general level, were that behavioral and psychosocial factors are consequential for health (physical and mental). The purpose of the Cognitive Project was to determine how cognition is related to overall mental and physical health. Specific goals were: (1) to characterize the nature and range of midlife cognitive performance, relative to those younger and older, across multiple domains in a nationally representative sample (MIDUS); and (2) to examine the relationship between biopsychosocial factors (e.g., SES, health status, health-promoting behaviors, metabolic and cardiovascular biomarkers, depression, personality, control beliefs, stressful life events) and individual differences in cognitive functioning. The development of a cognitive battery for the second wave of testing of the Midlife Development in the United States (MIDUS) study provided an opportunity to examine the cognitive performance of young, middle-aged and older adults from a wide range of education levels in a large-scale, national sample. As part of the Cognitive Project of the MIDUS II the Brief Test of Adult Cognition by Telephone (BTACT) (Lachman & Tun, 2008; Tun & Lachman, 2006) was administered. More information about the BTACT can be found at The BTACT represents the first comprehensive cognitive battery, including measures of speed and reaction time, to be administered by telephone to a national sample across the adult years and into later life. With a response rate of over 86 percent for the cognitive testing component of the MIDUS II, a cognitive data set of unprecedented range in terms of age, gender, socioeconomic status (SES), education, and geographic diversity was produced.

Series: Midlife in the United States (MIDUS) Series

Access Notes

  • 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.


National Survey of Midlife Development in the United States (MIDUS II): Cognitive Project, 2004-2006 - Download All Files (24.989 MB)

Study Description


Ryff, Carol D., and Margie E. Lachman. Midlife in the United States (MIDUS 2): Cognitive Project, 2004-2006. ICPSR25281-v6. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2017-11-17.

Persistent URL:

Export Citation:

  • RIS (generic format for RefWorks, EndNote, etc.)
  • EndNote XML (EndNote X4.0.1 or higher)


This study was funded by:

  • United States Department of Health and Human Services. National Institutes of Health. National Institute on Aging (5-PO1-AG20166)

Scope of Study

Subject Terms:    adults, cognition, cognitive functioning, cognitive impairment, cognitive processes, health, health status, life satisfaction, mental health, physical heallth

Smallest Geographic Unit:    No geographic information is included other than for the Milwaukee cases.

Geographic Coverage:    United States

Time Period:   

  • 2004--2006

Date of Collection:   

  • 2004-02-16--2006-03-21

Unit of Observation:    individual

Universe:    Adult noninstitutionalized population in the contiguous United States

Data Type(s):    experimental data, survey data

Data Collection Notes:

All data files in the MIDUS study (both longitudinal and cross-sectional) can be linked using a key variable called M2ID.

The DDI codebook (PDF file) and the XML file (contained in a .zip package) released by ICPSR were provided by MIDUS and were not changed in any way by ICPSR. These original files do not reflect any of the processing done by ICPSR.

The title of this study was changed from National Survey of Midlife Development in the United States (MIDUS II): Cognitive Project, 2004-2006, to Midlife in the United States (MIDUS 2): Cognitive Project, 2004-2006, on May 12, 2017.


Sample:    All respondents participating in MIDUS II (the longitudinal follow-up to MIDUS [see ICPSR 2760] or the Milwaukee study [see ICPSR 22840]) were eligible to participate in the cognitive assessments.

Weight:    Weighting datasets and documentation can be found in MIDUS 1 (#2760) and 2 (#4652).

Mode of Data Collection:    computer-assisted telephone interview (CATI), cognitive assessment test

Response Rates:    Completion rates (the denominator is the number of cases successfully completing the initial phone survey) for the cognitive assessments were: Main RDD -- 85 percent, Sibling -- 92 percent, Twin -- 87 percent, and Milwaukee -- 52 percent.

Presence of Common Scales:    Rey Auditory-Verbal Learning Test WAIS-III (backward digit span test) Verbal Fluency-Animal Category Attention-Task Switching/Reaction Time Tests Inductive Reasoning Speed of Processing Tests

Extent of Processing:   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:

  • Created online analysis version with question text.
  • Checked for undocumented or out-of-range codes.


Original ICPSR Release:   2009-05-04

Version History:

  • 2017-11-17 This collection is being updated, per request from the PI, to reflect a title change; the corresponding downloadable files are only being updated to reflect the title change, where applicable.
  • 2013-04-29 Update to documentation files.
  • 2013-03-15 Codebooks in XML (DDI 3) and PDF formats have been created.These were provided by the PI. There have been minor changes to the data that are detailed in the readme file.
  • 2011-10-25 The document titled DDI codebook has been renamed Codebook.
  • 2010-11-01 The data have been updated and now include 306 cases from the Milwaukee subsample. The documentation has also been updated to reflect this change.

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