1) Due to budgetary constraints, not all of the COGA data were able to be genotyped for GAW14; therefore a subsample of Wave 1 and Wave 2 data was selected for genotyping. This subsample selection was based on large family size and interview status to obtain informative pedigrees. Electrophysiologic measurement was not a criterion for selection. This resulted in the selection of 1,353 subjects for genotyping in GAW14. (Note that the GAW sample consists of 1,614 individuals, because additional non-genotyped individuals were included for linking in the pedigrees).
