I'm not sure which study you are talking about, because the USMC has been fighting it for several decades - and conducted many studies to back their position. I wrote a paper on the subject many years ago, it is a very complicated issue - lots of very obvious and undeniable cons, with a few potential pros. One of the funnier cons that I remember was the statistical analysis of female service members' pregnancy rates prior to deployment. For some reason, as soon as deployment time comes up - a great many females find themselves impregnated and unable to go overseas... Apparently the problem is so bad that many commanders don't include females in the total organization count for predeployment planning. Also, the USMC is pretty much the only branch that would benefit from the potential pros - pushing problem-solving and ethics further down the chain of command. I'm guessing that they've done the math and decided that it would still be a net negative.
Pregnancy is a stickier issue, and for the Corps is more problematic because they historically have had much higher undeployable numbers than the other services. Unplanned pregnancies are lower than the civilian population for officers and senior noncoms, but are roughly average for junior enlisted when adjusted for socioeconomic factors. Military policies forbidding any access to abortion procedures on-base also makes it harder to terminate unplanned pregnancies and, often when deployed overseas, impossible, which could account for some of the statistical correlation you cite. Actually, if you happen to dig up a citation to that study, I'd love to read it!
> ...but I'd like to see an analysis of the field effectiveness of units in combat as well as training.
That would only be an effective analysis if a long term trial were to be conducted, 10 years might be enough. The context of this conversation is kind of funny, because the USMC's success is rooted solidly in homogeneity - the long term impact is the real point of concern.
> ...I'll note that plenty of female Marines (and soldiers) have over the past decade and a half of war operated effectively as light infantry in high OPTEMPO environments...
Not really. I can't really say it without sounding like an asshole, so I won't try :) The infantry experience is very different, and comprised of much more than simply being in a non-permissive environment - not comparable.
> ...the enemy doesn't care if you're an officer leading an infantry platoon or a logistics convoy.
Oh yes they do, it would be totally insane to conduct an attack on an infantry platoon in the same way you would attack a logistics convoy. In 2006 my unit took over a formerly national guard AO, they got direct fire pretty regularly - and so did we for the first few days. After the locals figured out that we weren't national guard, we experienced no more direct fire - just IEDs and mortars. I don't think it is a stretch to say that females would likely be treated differently by the enemy.
> Unplanned pregnancies...
I guess I was too subtle, I wasn't talking about unplanned pregnancy. This sort of behavior is not limited to females of course, I once saw a guy shoot himself in the foot, but the pattern of predeployment medical issues is much clearer with the females.
Could you point to some of this research? I'd be interested to learn more about research that has been done.
Whether Twitter needs black engineers to secure its higher-than-average black userbase is, I think, at best dubious (as Gibson tells us, users find their own use for things), but it might want to reconsider its stance as Wall Street begins side-eying its valuation. Meanwhile, as Brian Brackeen of Kairos put it, the unicorns' failure means startups have a lot of potential talent to grab....