Since its inception in 1989, COGA has used a family design, recruiting multigenerational families affected with alcohol use disorder (AUD) through probands in treatment for AUD, and a smaller set of community comparison families. To date, there have been 17,878 individuals in 2246 families who have participated in one or more of the assessment waves. Data collection has focused on different participant subsets over time, depending on the research emphasis. There have been four principal data collection waves that may be broadly described as follows: (a) “Wave 1” initial ascertainment and assessment from 1991 to 1999 (initial AUD case and community families); (b) “Wave 2”: follow‐up of individuals in Wave 1 and other family members not assessed at Wave 1, as well as families from a new research site from 1996 to 2005; (c) the “Prospective wave” from 2004 to 2019 which focused on assessments of youth ages 12–22 (born 1982 or later) in both case and comparison families at 2 year intervals; and (d) the current, “Lifespan” wave, begun in 2019, in which previously assessed participants now in midlife
