ABCD General Data
DOI: 10.15154/z563-zd24 (Release 5.1)
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:
- We joined visit completion date to the school dates to identify the school attended.
- 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.
- 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.
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