the trait is uniformly measured and the allele frequency is similar, the method is approximately equivalent to meta-analysis of sample-size-weighted Z-scores. Yet, the method accounts for between-study heterogeneity in imputation accuracy and allele frequencies. The use of a fixed effects model, the most common approach in GWAS meta-analysis of single ancestry groups, appeared acceptable given the apparent lack of substantial meta-analytic effect heterogeneity (see Cochrane’s Q and I2 statistics in Supplementary Tables 1–5).
