> In my opinion, the biggest problem with the google-style interview (other companies do the same thing) is that you can practice and get better at it. In fact, you can probably improve how well you do so much that even a mediocre developer can come out looking very good.

It's a popular meme on HN that people's intelligence and abilities are fixed from the start. In reality, they're quite plastic and improve over time when they're put to a use.

Note that outside of few companies such as Google, Microsoft, Apple and some start-ups (and even for good chunk of roles within those companies) great deal of programming involves wiring together components somebody else wrote, while working around bugs in those components. There's nothing wrong with that, in fact, if someone already solved a problem adequately enough it's your duty to build an application based on that solution rather than re-invent the wheel, this time with new and exciting bugs (I'll confess to having done that bunch of times, going as far as writing my own RNG once). If you want to understand how the "magic" of those components works (so that you could get some of the most intellectually rewarding jobs which involve creating such "magic"), you have to do that on your own time.

Thus, if you have a regular programming job specific portions of your intelligence will atrophy as they're not being used. If you've found a job that is intellectually stimulating, then you have no reason to interview elsewhere unless you're grossly underpaid, have to commute to the North Pole and write firmware for machines that torture baby seals.

When an interview candidate is truly smart e.g., can figure out a more puzzle-like problem without ever having seen them before, that's great and respectable. Give her a few extra points. When a candidate shows persistence, passion (coding in her spare time on the sort of problems you typically don't see in day to day work), curiosity (learning about skip lists just because they're... really cool) and a way to apply her intelligence (even if that's not genius level) to her field of work (being able to keep multiple levels of indirection e.g., pointers and recursion in her head) that's even better.

In my (so far, limited) experience in the industry I've noted that there are several types of programmers:

1) The "99.9th percentile" or "10x" programmers. They usually have an innate ability that was well nurtured from the beginning. There's only a handful of them, fairly equally distributed between Google (prior to it Sun, Bell Labs), start-ups, academia and quantitative finance / hedge funds. It's very visible: they'll solve problems quickly, they'll write code and get many things right the first time. They'll spot tricky concurrency issues by just looking at the code. If you manage to find one, by all means move mountains to hire them. Problem is, why would they join you? Money is not a motivating factor for them (not always out of principle: they're generally well off already) and companies bend rules for them (e.g., let them work from home or open offices in their home town if they're not local). If you want to hire them, hire all of their (respected) coworkers and friends, first. May be then (if things turn sour at their workplace) they'll consider you. The other way is to spot one amongst the crowd of interns or fresh graduates (Joel recommends that).

2) Visible poor ones. Typically very nice people, sometimes highly persistent and entrepreneurial but without the ability and/or education (self or formal) needed to succeed in an engineering discipline. They may still be smart: surprisingly, I've seen several people with advanced degrees in Mathematics and Computer Science that fit that bill (how that could happen evades me). Typically these are the people that are always on the market: who can't do fizz buzz, reverse a linked list, etc... It's trivial to filter them out. If they're really eager to be involved in software development, project/product management may be a right fit for them if they're otherwise smart and technical (see "The Russian Lit Major" by Rands for more on that). Oddly enough, I've seen people like that found profitable and sustainable small businesses (even if they weren't technology start-ups with home-run exits).

3) Everybody else. They're intelligent and educated (again, whether self or formally) enough to be <b>a programmer</b> but it either took or will take them work to be a great one. They have no genial ability, they will write code that has bugs and will have to sit down at a debugger to figure out why their code doesn't work. Odds are most people on HN fall into that category. Question is, how persistent are they at this? Do they give up after getting a cryptic error message? Have they had enough experience to avoid common causes of bugs? Are they willing to take time to improve themselves (to be able to "work magic") rather than being content to be typical enterprise developers?

People in this category are very well capable of being 95-98th percentile programmers. It just takes practice (and not just paid practice at work) in addition to dedication and passion, not just innate qualities (such some forms of intelligence), to get to that level.

They range in their current ability from "framework developers" (who don't care how something is implemented, but know a particular implementation well enough to get the job done) to what I called "95th-98th percentile" developers. Finding people on the upper end of that range (who have worked/studied their way to that place) is what programming questions should be aimed at, not just at finding general intelligence.

Majority of employees in serious technology companies (Google et al) as well as a most start-up founders (with a few exceptions of some true "10x" programmers e.g., Bill Joy of Sun) fit that bill: they persisted at and practiced something they loved for a long period of time and became great at it. There are more of these people than there are "10x" programmers and many have earned the respect of the "10x" programmers and are going to be able to attract them to your organization in a "get an already great programmer, get introduced to his genius friend" deal.