COGA as a consortium relies on the integrative analyses of these four broad domains of data. The nearly 600 manuscripts generated with COGA data since its inception underscore the importance of ensuring that all COGA scientists (~60), and our external collaborators, as well as those analyzing COGA data that they obtain from NIH‐supported resources (see below) have access to the same high quality of harmonized behavioral, clinical, genomic and brain function data that was systematically quality‐controlled, not only at the individual level but also within the large COGA pedigrees so as to maintain the intended study design. From the outset, COGA utilized a single linking variable (record identifier, but without personal identifying information) that was unique to each family, and a sub‐variable for individuals within each family indicative of their relationship to the proband. A core harmonized set of gene‐brain‐behavior data are available to all COGA investigators while additional data are harmonized across the various waves of data collection as the analytic needs of investigators arise—for instance, while some research questions may require the cross‐sectional coding of a lifetime measure
