I hasten to add that it isn't perfect. We hire across the intro-extraversion spectrum, but there's an ongoing concern that we're biased towards extraverts. Especially in Labs, which is the consulting wing.

Another problem is that many candidates are just plain nervous. We do our best to set people at ease and to be upfront that there's no right or wrong or trick answers. But interviewing is just scary. I expected to fail and so felt no pressure -- had I felt that more was on the line, maybe I'd have done worse.

The third -- this is a very common negative opinion -- is the argument that we don't give candidates a fair opportunity to show their expertise.

We will usually try to assign one project where their résumé claims expertise and another one that they're unfamiliar with. The former to take a sounding of their expertise, the second to get a feeling for their approach to the unknown.

It's not always possible to do this, simply because it's a vast field and candidates come with very varied backgrounds. And those candidates who are declined often feel that we've denied them a fair chance by throwing them into an unfamiliar technology.

These are all fair criticisms. My best answer is: we are not trying to trick or exclude anyone upfront. Ultimately the hiring decision is made by future peers, so we want to be fair but firm.

Hiring is just hard.