How Effective are Technical Interviews?

What is the question I may ask?

It would be interesting if a large company that could afford to do so (say, Google) made an attempt to experimentally test that question. It'd take some thinking to design a useful study with some sort of blindness, but something along the lines of: have everyone do the technical interviews, but then for some subset of interviewees, the final decision-maker chooses whether to hire or not based on a coin flip instead of based on the interview. Then assess the performance of each group of hires a year or two later.

Disclaimer: may or may not be legal; I'm no employment-law expert, so have no idea if "not hired due to coin flip" would be a grounds for suing.

I have a sizable and growing portfolio of code I've written: some complicated algorithm stuff, some open source contributions; things like that.

No one ever looks at it. I'm starting to wonder why linked lists are so important to employers.

I work for one of those big companies. After going over trouble spots in the resume and asking why they want to work here, I tend to ask one or two very similar questions that 1) force candidates to do nontrivial coding, algorithms, and design while writing a complete program, and 2) elicit a wide range of responses. I don't require a certain language or ding on syntax. We usually spend the rest of the hour on the question.

In general, bad candidates get me hinky in the resume portion (or worse, don't really want to work here!) then crash and burn on the programming question. Borderline candidates do ok in resume but make me feel like they're not that comfortable programming. Great candidates usually do something clever during the problem.

I believe that doing homework isn't convincing. It's too easy to cheat. That's probably why the commenter elsewhere on the thread got bounced from Google. Doing week-long trial runs would be ideal, but impossible at my company. We sometimes go contractor-to-hire though.

Can you be a great programmer and fail my interview? I think it boils down to three things: skills, communication, and pressure. If you lose your skills and communication under pressure for an interview day, you probably won't survive in my environment over the long haul.

It sounds like the AJAX web app was designed to test your sense of taste and your ability to get things done, and the Javascript question was to test whether you've ever done anything numerical in JS.

('4'+4)-4 is 40, whereas (4+4)-4 is 4. There are a lot of people who glue a few things together in Javascript and PHP and call it a day, and their filter against those is imperfect. Interviews as a whole are less informative than actually working with someone.