All 453 men were located approximately 10 years (T10) after the initial testing when 99% completed semi-structured interviews about their interval alcohol and drug use, and corroborating data was gathered from an additional informant, usually a spouse. At the 15 year followup (T15), 98% of the original subjects and resource persons were evaluated using an interview expanded to include material from the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) instrument and to gather information about additional areas of functioning including peer drinking, alcohol expectancies, and drinking to cope (Bucholz et al., 1994). The same data collection methods were used to gather information on these variables during the 20-year follow-up (T20, approximately 96% retention), and as part of the ongoing 25 year followup (T25) protocol with an estimated 94% data retention over the 25 years.
