I interviewed at Google. Didn't get the gig, but while I was in the office, it did seem like their engineers were mostly 30+ somethings. I didn't see a lot engineers there that looked like fresh grads. I know more than half the engineers working there interview two or more times before getting an offer.
Google, and most larger tech companies, optimize their hiring process to aggressively deny candidates if they aren't a slam dunk. The negatives that come from hiring a bad engineer far outweigh the positives that come from hiring a good engineer.
Not saying there isn't an age bias, just not an obvious one I noticed.
No statistics per say. Programmers are a different animal that say a job like tech support or customer service. Stuff they do, code they write, will stick around in your system for a while, and is non-trivial to remove or fix. If a customer service rep does a bad job you can fire them and going forward is a clean slate. But high turn over for software engineers leads to more technical debt. Lower quality programmers lead to exponentially greater technical debt. Also the cost of hiring someone in terms of dollars is not small.
So think about it from Google's point of view. You take a risk, hire a programmer that doesn't pan out. You fire him after 6 months. That's 6 months of salary and benefits. 6 months of bad code sitting in your code base. 6 months of lower productivity for whoever was on that person's team. And probably another 6 months after that of clean up either ripping out bad code, or worse, leaving passable code that turns bad at a later date causing even more work.
It is better to just take no action on a potentially good candidate and let them try again in a year than it is to take even a small risk on someone who might cause things to snowball.
What in America sorry I am ROTFL here! didn't seem to stop jack Dorsey making a lot of people redundant or MS using stack ranking to fire the lowest 10%
Google, and most larger tech companies, optimize their hiring process to aggressively deny candidates if they aren't a slam dunk. The negatives that come from hiring a bad engineer far outweigh the positives that come from hiring a good engineer.
Not saying there isn't an age bias, just not an obvious one I noticed.