The design of COGA as a large, multi‐modal, family‐based study that was enriched for AUD liability also brings forth certain caveats. Large families that are densely affected may not be representative of the constellation of genetic and socio‐environmental risk and resilience factors influencing AUD in the general population. COGA has contributed to large, collaborative studies (e.g., References 5, 55, 69) that bring together data from many different studies with different ascertainments, and thereby enriched those studies. However, it is worth noting that effect sizes of loci and of polygenic scores may be influenced by our ascertainment strategy. Reassuringly, many COGA findings have been replicated in other samples (e.g., References 76, 77, 78, 79).
