Comments on the entropy-based transmission/disequilibrium test.

It has recently been claimed in this journal (Zhao et al. in Hum Genet 121:357-367, 2007) that a so-called "entropy-based" TDT test has improved power over the standard TDT test of Spielman et al. (Am J Hum Genet 52:506-516, 1993). We show that this claim is contradicted by standard statistical theory as well as by our simulation results. We show that the incorrect claim arises because of inappropriate assumptions, and also show that the entropy-based statistic has various undesirable properties.