et al. (2011) appear to conflict with those of a recent study by Huang et al. (2009b), which found that power drops quickly with mean R2. We believe that the Zheng et al. (2011) results more accurately reflect this relationship because the mathematical model of imputation errors used by Huang et al. ignores the correlation of imputation error across individuals, which could be substantial, e.g. at hard-to-impute SNPs.
