It is important to consider whether further increases in sample size will continue to yield new, worthwhile insights. The new discoveries achieved by larger GWA studies take the form of new associated loci, and of new variants at known loci. Each of these has different potential benefits. New loci can aid in the identification of new causal genes or pathways, new variants can help define mechanism or causal genes at associated loci, and both new loci and new variants increase the phenotypic variance explained, which could aid in prediction.
