ABCD General Data

DOI: 10.15154/z563-zd24 (Release 5.1)

Published

January 15, 2025

List of Instruments

Name of Instrument Subdomain Table Name
Youth Instruments
Longitudinal Tracking Administrative abcd_y_lt
Latent Factors Demographics abcd_y_lf
Parent Instruments
Demographics Demographics abcd_p_demo
Occupation Survey Demographics abcd_p_ocp
Screener (Study Eligibility) Screener abcd_p_screen
Screener (Follow-Up Scheduling) Screener abcd_p_screen_l

General Information

An overview of the ABCD Study® can be found at abcdstudy.org and detailed descriptions of the assessment protocols are available at ABCD Protocols. This page describes the contents of various instruments available for download. To understand the context of this information, refer to the release note Start Page.

Instrument Descriptions

Youth Instruments

Longitudinal Tracking

Release 5.0 Data Table: abcd_y_lt

Measure Description: The Longitudinal Tracking instrument includes various information about the participants over time that users will find useful in their longitudinal analysis. It provides information about the date that a given event was started (variable interview_date) and the participant’s age in month at that time (variable interview_age). It further describes the setting (on-site, remote, or hybrid) in which the visit for this event was completed (variable visit_type).

Furthermore, the table includes several variables that can be used to account for clustering of participants into different groups:

Sites

The site_id_l variable describes sites by numeric code. The translation of site_id_l codes to site acronyms is available in the Changes and Known Issues Release Notes file that authorized users can download here.

Families

Participants belonging to the same family share a family ID (variable rel_family_id). In this release we additionally include a birth ID (variable rel_birth_id) which provides a unique ID for individuals within the same family that share the same birthdate. This variable can be used to differentiate between siblings and twins/triplets within the sample (see also the Genetics release note).

Schools and school districts

A pseudo ID was generated and assigned to each district so that users can cluster participants by school district (variable district_id). A pseudo ID was also generated for school so that users can cluster participants by the school they attended (variable school_id). In cases where informants reported that the participant was homeschooled, school_id was recoded to ‘0’.

We used the following process to identify school(s) for each participant:

  1. We joined visit completion date to the school dates to identify the school attended.
  2. In cases where no schools were available based on this criterion, we then matched the grade at a given school with the grade reported at the visit to identify the school attended.
  3. If necessary, we used the event name information (e.g., 1_year_follow_up_y_arm_1) as a fallback option for school identification.

To reduce the risk of participant identification, data were made available only for districts and schools with >= 10 participants. Because of this, the pseudo school ID is not available for approximately half of the participant cohort.

ABCD Subdomain: Administrative

Number of Variables: 8

Notes and special considerations:

In 5.0, we have corrected a small number of errors in the site ID variable. Please disregard data about site in prior releases in favor of the 5.0 release data.

Latent Factors

Release 5.0 Data Table: abcd_y_lf

Measure Description: The Latent Factors table contains three variables that users may find useful in their analysis. These factors include: 1) a general latent factor of economic, social, and physiological well-being, 2) a latent factor for youth perceived social support, and 3) a latent factor for perinatal health.

ABCD Subdomain: Demographics

Number of Variables: 3

Notes and special considerations: None

Parent Instruments

Demographics

Release 5.0 Data Table: abcd_p_demo

Measure Description: Extensive list of parent reported demographics about the youth, themselves, and family. This includes race and ethnicity. Note that this table includes the ACS (American Community Survey) Ranked Propensity score that imputed ranked propensity weight. The ranked propensity weight merges the ACS and ABCD data (with missing data imputed), estimates the propensity model, computes and scales/trims the propensity weights and finally rakes the scaled weights to final ACS control totals by age, sex and race/ethnicity.

Warning

A 5-level race/ethnicity variable (race_ethnicity) has been constructed based on the parent and/or caregiver report of the youth’s race and ethnicity during the baseline visit. The algorithm for calculating the variable considers Hispanic ethnicity first and then categorizes based on the race/ethnicities selected. The categories are:

  • Hispanic
    • If Hispanic/Latino/Latina is selected
  • White
    • If White is the only race selected & Hispanic/Latino/Latina not selected
  • Black
    • If Black is the only race selected & Hispanic/Latino/Latina not selected
  • Asian
    • If Asian is the only race selected & Hispanic/Latino/Latina not selected
  • Other
    • If Other race is selected & Hispanic/Latino/Latina not selected
    • If more than one race is selected & Hispanic/Latino/Latina not selected

The following is the R code used to reproduce the race_ethnicity.

Important Responsible Data Use and Analysis Considerations

Using a large-population datasets such as ABCD requires responsible conceptualization, use, and reporting of race and ethnicity to avoid the further stigmatization of historically minoritized groups. This paper has important considerations and recommendations for conceptualizing, contextualizing and communicating issues related to race and ethnicity: https://www.nature.com/articles/s41593-024-01608-4

A 5-level race/ethnicity variable has been provided in the dataset. Depending on the study design, race and ethnicity can be used differently in data analysis. In the following paper using ABCD study data, race/ethnicity included White, Black, Hispanic, Asian, or Other race/ethnicity and racial subgroups for children that identified as Other race/ethnicity. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8860403/

ABCD Subdomain: Demographics

Number of Variables: 274

Notes and special considerations: None

Occupation Survey

Release 5.0 Data Table: abcd_p_ocp

Measure Description: Asks caregiver about their own and their partner’s occupation and job category according to the ACS job classifications

ABCD Subdomain: Demographics

Number of Variable: 54

Notes and special considerations: None

Screener (Study Eligibility)

Release 5.0 Data Table: abcd_p_screen

Measure Description: Data from the Screener Instrument that was used to determine study eligibility prior to enrollment. This also includes estimates of twin participants physical similarity.

ABCD Subdomain: Screener

Number of Variables: 80

Notes and special considerations: None