Classification matrices for selected regression models illustrating the prediction accuracy of variables examined either individually or in combination.

aThe percentage of pregnancies correctly classified as a proportion of those blastocysts predicted to result in a successful pregnancy. bThe percentage of embryos correctly classified as resulting in no pregnancy and pregnancy (the hit ratio). cConventional variables based on the stage and morphological quality code of blastocysts at the time of transfer. d,eDifferent letters indicate a significant difference (P<0.05). Data were analyzed with the Yates' corrected χ2 test.