The GENEVA studies analyzed to date are not family-based, but the Addiction and Lung Cancer projects included a small number of HapMap trios as genotyping controls. For each SNP in the Addiction project, the Mendelian error rate was calculated as the number of errors detected divided by the number of families in which the offspring and at least one parent have non-missing genotypes. Among the 1,040,106 SNPs with a possibility for error detection, 99.1% have no errors and the mean error rate is 0.04%.
