This thread, and a similar thread recently -
https://news.ycombinator.com/item?id=20162777, just solidifies my desire to ask for algorithmic whiteboard type questions.
Assuming all other things are equal, obviously anyone will choose the candidate who can do these questions vs one who cannot.
The problem, obviously, is that all other things are seldom equal IRL. So, the issue now becomes : Would you rather hire someone who has a solid github profile but can't whiteboard algos, or someone who doesn't have any past portfolio but can ace whiteboard algos.
If you give me 20 years, I could probably get a PhD. Given ENOUGH time, anyone could theoretically achieve anything. But the differentiator between candidates happens when the clock is ticking.
I, and most other employers, are not looking for perfect answers. We want to know how you approach a problem under these constraints : short time, high pressure, unseen problem.
We want to know whether you are the type who chokes. It tells us that your desire to look good in front of someone (or conversely, your fear of looking bad in front of someone) fills up your mind more than your desire to solve a problem.
Would you choke if you mom asked you the same question - No, because you don't fear being judged, right ?
We want a similar trait in our developers. We want you to GIVE VERY LITTLE SHIT about what we think of you, at least for the next 30 minutes. We want you to have enough control of your mind to TEMPORARILY ignore our existence and focus on the problem at hand.
Granted, such scenarios occur rarely IRL, but it tells us a lot about how much control the person has over their psyche, how honest they are about their limits, what they do when they reach their limit etc. It's as much a behavioral test as an IQ one.
Having said all that, not all companies need non-choking geniuses. Choking geniuses work fine for many.