Another interesting tidbit from that unpublished Stanford study, a draft of which is available here, is that there is a category of female members of Congress who do not make superior legislators to men: political widows. The researchers posit that this is because widows, unlike other female candidates, don't face higher hurdles for entry-on the contrary, they often benefit from the sympathy factor, as well as name recognition. The typical political widow also tends to have more confidence in her ability to win, perhaps because she figures that if her late husband could do it, so could she. So she is more likely than most women to run for office. You could quibble, I'm sure, with the criteria to measure success, but it's a provocative notion since this has traditionally been a pretty common path to legislative office, for women. Also provocative: Their research suggests that the most effective female legislators are from conservative districts, because they face the highest barriers of entry. Survival of the super-fittest.