[gambling8nt]

The original paper by Hyde and Mertz can be found at http://tctvideo.madison.com/uw/gender.pdf . In it, the authors reference data from the Program for International Student Assessment as their primary evidence in attempting to discredit the Greater Male Variability Hypothesis (apart from their discussion of differing degrees of female membership on IMO teams). Careful examination of the 2006 PISA data, however, indicates a positive correlation between variance ratio and mean performance amongst OECD countries with above average performance (selected to control for availability of educational resources, and overall social stigma against mathematics). This suggests that countries which have taken action to reduce Variance Ratio in order to equalize educational outcomes have also reduced overall mean outcomes.

In other words, countries which have successfully suppressed greater male variance (if it is inherent) or have through cultural engineering increased apparent female variance, have done so at the cost of reducing mean outcome.

It is worth noting, however, that this result was achieved by looking at countries that were assumed to already have adequate educational resources, and have already achieved above average mean outcomes--presumably through some sort of cultural emphasis on the value of mathematics. Both of these effects appear greater than that of suppression of male variability.