National Longitudinal Study of Adolescent to Adult Health


The National Longitudinal Study of Adolescent to Adult Health (Add Health) is a longitudinal study of a nationally representative sample of over 20,000 adolescents who were in grades 7-12 during the 1994-95 school year, and have been followed for five waves to date, most recently in 2016-18. Over the years, Add Health has collected rich demographic, social, familial, socioeconomic, behavioral, psychosocial, cognitive, and health survey data from participants and their parents; a vast array of contextual data from participants’ schools, neighborhoods, and geographies of residence; and in-home physical and biological data from participants, including genetic markers, blood-based assays, anthropometric measures, and medications. Ancillary studies have added even more data over the years. Data from the project are available in various forms and have been analyzed in thousands of publications in peer-reviewed journals.

The Add Health study website is a good source of information about the study. It contains user guides, codebooks, and a list of publications that utilize the data.

Add Health currently has five waves of data available. Below is information about the core data.

  • Wave I: 1994-95; public-use sample size 6,504; restricted-use sample size 20,745
  • Wave II: 1996, public-use sample size 4,834; restricted-use sample size 14,738
  • Wave III: 2001-02, public-use sample size 4,882; restricted-use sample size 15,197
  • Wave IV: 2008, public-use sample size 5,114; restricted-use sample size 15,701
  • Wave V: 2016-18, public-use sample size 4,196; restricted-use sample size 12,300

The image below describes the longitudinal design of the study.


Public-Use Data

There are both public-use and restricted-use data files available. The public-use data sets contain all the survey data from In-Home Interviews but only for a subset of the full Add Health sample. Public-use data doesn’t contain ID numbers of friends, siblings or romantic partners, nor does it contain files on Obesity and Neighborhood Environment, genetics, disposition, political context and alcohol density. These files require a restricted-use contract. The Inter-university Consortium for Political and Social Research (ICPSR) distributes the Add Health public-use data at no charge through its Data Sharing for Demographic Research (DSDR) project. Public-use data are available for download from the DSDR website. To download the data, returning users must log in to their MyData account; new users are required to create a MyData account. MyData is the user registration and authentication system for the ICPSR and DSDR websites. The system uses an email address as a login ID and requires a password.

We recommend downloading the data through ICSPR. Data from the in-home questionnaires, biomarkers, and supplemental data can be downloaded in separate files in numerous formats along with accompanying documentation. ICPSR also provides a searchable variable list.

Restricted-Use Data

The extensive restricted-use data, available by contractual agreement, contains data for all study participants and will be distributed only to certified researchers who commit themselves to maintaining limited access. To be eligible to enter into a contract, researchers must have an IRB-approval letter, security plan for handling and storing sensitive data, and sign a data-use contract agreeing to keep the data confidential. Please note that data linkages are not allowable with a restricted-use contract. To learn more about the restricted-use data and how to apply for restricted-use data, please access the CPC Data Portal.

Sample Code

The code we provide is based on the ICPSR public-use data sets for the in-home questionnaire. These files represent the core of the Add Health study data and contain thousands of variables. We recommend downloading the program-specific data files from the ICPSR archive as we use these data for the basis of the code. The code can be found here.