[mike_h]

When women are around, there's more at stake for men. They need to be more competitive but also more well-behaved (they're being judged not just on performance but also on character).

There could be an analogous effect on the women, I don't know.

In my Silicon Valley experience, a team without women is a disadvantaged team indeed, and not just because they make the men better. But not acknowledging the potential contribution of this dynamic is kinda surprising to me.

[ajscherer]

That doesn't really explain why the groups with 100% women did so well, or why the groups that were 50/50 did worse than the groups of all men or all women. Maybe I'm trying to take more information from the chart than is really there.

[mike_h]

Hm, I missed that link to the chart before, and I was trying to respond to the "cognitive diversity -> effectiveness" discussion. You're right: it's hard to see the chart supporting my claim. (There are some hints at a sweet spot there in the middle, except for that drop at 50/50!)

Link to chart: http://hbr.org/2011/06/defend-your-research-what-makes-a-tea...

[brettnak]

The variance, just from glancing at that chart seems extraordinarily high. I'd be very hesitant to draw conclusions.

[jackpirate]

Factoring in the variance, it looks to me like groups that had an even split did the best. Groups predominantely of one gender suffered.

The "women are better" trend line may partially be accounted for from the fact that there were simply more groups with more men.

[chrischen]

Could be that in groups without women, men underperform because of a lack of stimulation.

[nl]

I think this is the most important part, and provides the best explanation of the results:

part of that finding can be explained by differences in social sensitivity, which we found is also important to group performance. Many studies have shown that women tend to score higher on tests of social sensitivity than men do. So what is really important is to have people who are high in social sensitivity, whether they are men or women.

So it isn't men being more competitive - it's that teams with people who work well with others generally perform better. On average women are more "socially sensitivity" so more women will, on average, imply a better team.

[johnl]

I don't know if it's the male/female thing. I think it is a "amount of discussion" thing. Women discuss the topic more without being positional so a larger quorum is reached. The men are too hierarchy oriented which results in a small quorum. So 50% would be optimum, the women force the discussion, the men force the decision. %100 women would not be optimal but still better than the men.