"A company looking for new hires can't give everyone a month-long trial to see what their ability is firsthand, so credentials like GPA and degree serve as a heuristic."
This is just corporate propaganda. GPA has no correlation with work performance, it's only used because it's a legal way to keep minorities out of the workforce.
I'd like to see some reliable studies to back up this statement. I don't see how this could be true when adjusted for variations in programs and schools. If I'm hiring twenty programmers from the same school who graduated from the same program at the same time, you're telling me that if I hire 10 people who barely graduated with a 2.0 GPA and ten people who busted their ass and graduated with a 4.0 GPA, the first group won't outperform the latter? Why would that be true?
It's only used because it's a legal way to keep minorities out of the workforce.
Bullshit. Corporations don't give two shits if there are minorities working for them, as long as they're making them money. This sounds like a viewpoint that drove whatever study came to the conclusion in the first part of your sentence, if there even was such a study.
This is just corporate propaganda. GPA has no correlation with work performance, it's only used because it's a legal way to keep minorities out of the workforce.