Accuracies of imputed genotypes in 59,000 SNPs (y axis) versus a summary of the LD patterns surrounding them (x axis). The summary of LD is a weighted average of the pairwise D' between each SNP to be imputed and all other SNPs in the same chromosome with weights that are calculated as . In the formula, d
is the physical distance between the SNP to be imputed and the ith SNP, in 100 kb, and d
' is the estimate of LD between the same two SNPs.