In the discovery phase of our GWAS of general risk tolerance (n = 939,908), we conducted a GWAS using the UK Biobank (UKB, n = 431,126) and then performed a sample-size-weighted meta-analysis of those results with GWAS results from a sample of research participants from 23andMe (n = 508,782). The UKB measure of general risk tolerance is based on the question: “Would you describe yourself as someone who takes risks? Yes / No.” The 23andMe measure is based on a question about overall comfort taking risks, with five response options ranging from “very comfortable” to “very uncomfortable.” The genetic correlation9 between the UKB and 23andMe cohorts (r^g = 0.77, SE = 0.02) is smaller than one but high enough to justify our approach of pooling the two cohorts (see Section 2 in the Supplementary Note of ref.10 for a theoretical demonstration of the merits of pooling cohorts despite moderate heterogeneity of phenotype measures).
