There is plenty of evidence for hiring discrimination of all sorts. Oceans of it. For example:

http://www.nber.org/papers/w9873

http://www.nber.org/papers/w5903

It happens in all sorts of industries and across a variety of axes. I've heard some argue that no, tech is different, that we're special, special snowflakes. But they have no evidence to back that, just feelings that bias is something only other people do.

2:1 hiring advantage for women in STEM

http://www.pnas.org/content/112/17/5360.abstract

As newmana mentions, there are issues with that study:

http://othersociologist.com/2015/04/16/myth-about-women-in-s...

And there are other studies I find more persuasive. E.g.:

http://www.pnas.org/content/109/41/16474.abstract

http://blogs.scientificamerican.com/unofficial-prognosis/stu...

In particular, I think the "switch the names" sort of study under realistic conditions makes it clear that bias is an issue. And it certainly matches widespread anecdotal opinions of nondominant groups in STEM fields.

The authors address the criticism here: http://www.huffingtonpost.com/wendy-m-williams/women-scienti...

Most of this criticism doesn't stand up to even a cursory reading. For example: "not only are there less women in STEM fields [..]" No shit, Sherlock, I don't think anybody disputed that.

Or the study that shows a disadvantage for mothers vs. fathers. The very same study shows a hiring/renumeration disadvantage for childless men vs. childless women. So yes, there's a dynamic here, but it's not male/female.

Also, the original comment I replied to was that outstanding developers are overlooked. None of the studies I've seen that show gender/racial bias (there are a few), deal with outstanding candidates (the Wiliams/Ceci did, IIRC). And incidentally not sure why you refer to "studies", your two links refer to the same single study.

There was another study (I think it was a different one) touted as showing hiring biases in STEM, except it turns out the study was performed in psychology departments.

Etc. etc.

There's some great information out there on the web in case you are interested, for example the Pinker / Spelke debate. Here's a quote:

"PINKER: But that makes the wrong prediction: the harder the science, the greater the participation of women! We find exactly the opposite: it's the most subjective fields within academia — the social sciences, the humanities, the helping professions — that have the greatest representation of women. This follows exactly from the choices that women express in what gives them satisfaction in life. But it goes in the opposite direction to the prediction you made about the role of objective criteria in bringing about gender equity. Surely it's physics, and not, say, sociology, that has the more objective criteria for success."

http://edge.org/3rd_culture/debate05/debate05_index.html

That study has many flaws especially in self selection:

http://othersociologist.com/2015/04/16/myth-about-women-in-s...

Common sense would tell you it does happen. It only takes one guy who'd rather hire a man than a woman and one qualified woman applying for that job.

I don't think it's a meaningfully large part of the explanation for the skewed distribution. I think there are deeper systemic issues for that. However, I don't think I've seen more than a handful of people say that quotas are in place because of discrimination either. From my experiences, I think my view here is by far the dominant one -- there is overt discrimination, but the bigger factor is more subtle. It's primary and secondary education, culture, socioeconomics, marketing and advertising to kids, in short, a bunch of stuff that serve to skew the pool of people even getting to the point of wanting tech jobs. Quotas aren't aimed at getting Klansmen to have to grit their teeth and hire a black guy. Quotas are an attempt to bootstrap the system -- maybe if we just dump a larger than normal population of minorities into our little world, it'll self-propagate through more minorities seeing this as a viable option, with the hope that a generation or two from now, you'll have the distribution you want naturally.

That's a good list, but I think you have left out subtle discrimination. Things like the IAT show that there's a great deal of implicit racial bias in the US. [1]

I also have never heard of a company actually having quotas. What I have heard is people gathering statistics and saying, "Hey, this looks pretty bad. What are we doing that might cause this? What can we do to fix our [generally unconscious and unnoticed] biases in our hiring processes?"

[1] http://www.washingtonpost.com/news/wonkblog/wp/2014/12/08/ac...

You're right, I haven't heard of actual quotas either. I just got a bit loose with using the parent commenter's terminology.

I agree on the subtle and implicit bias issue as well. I wasn't trying to be exhaustive, but that's a big enough issue that it ought to be specifically mentioned.

Companies primarily hire out of networks/referrals. If your company is full of white guys, and their friends are very likely to be white guys, you end up hiring white guys.