“The illiterate of the 21st century will not be those who cannot read and write, but those who cannot learn, unlearn, and relearn. ” — Alvin Toffler
I’ve seen much the same when hiring, and I’m glad to see Google taking this approach. Want to see how well someone can program? Ask them to write you a function. But don’t just grade them on whether they come up with the answer, rather look at how they got to their answer. What questions did they ask? Do they understand what’s going on?
The best indicators are when you ask them to do something they don’t know already. By traditional definitions, most people would fail if they didn’t get the answer you have. In my case, I’m always looking for who asks the right questions and shows me that they understand how to solve a problem.