The gender similarities hypothesis is untestable as formulated

Comments on the original article by Zell et al. (see record 2015-00137-002) regarding gender similarities and differences using a metasynthesis approach. The authors concluded that the average difference between males and females across psychological domains is relatively small (d = 0.21), with the majority of effects being either small or very small, thereby supporting Hyde's (2005) gender similarities hypothesis that males and females are similar on most psychological dimensions. Unfortunately, their study suffers from the same flaw as nearly all studies testing that hypothesis, namely that it does not provide a metric for either the psychological importance or relevance of the dimensions considered nor does it supply an individuation rule for counting dimensions.