In our primary GWAS, we study EA, which is measured as number of years of schooling completed (EduYears). All association analyses were performed at the cohort level in samples restricted to European-descent individuals. We applied a uniform set of quality-control procedures to all cohort-level results. Our final sample-size-weighted meta-analysis produced association statistics for ~10 million SNPs from phase 3 of the 1000 Genomes Project12.
