Overall workflow of HapMap SNPs assessment. If all the SNPs in HapMap or subset of SNPs in HapMap that can capture all other SNPs are identified in NIEHS, then classified them as set B. Otherwise, the genes are classified as set A. For the genes in set A, the performance in both NIEHS and HapMap are measured. For the genes in set B, the SNPs are assessed in the NIEHS populations.