There are two emergent schools of thought (at least) about technical team hiring: hire fast, fire fast (a play on the "hire slow, fire fast" adage), and no false positives. FeedBurner founder Dick Costolo has this to say:
I buy the hire fast, fire fast line of thinking for Sales Reps or VP
Sales roles but I don’t buy it for Engineering, Marketing, Finance,
etc. The problem with hire fast, fire fast in the engineering
department is quite simple: you don’t end up executing on the fire fast
part of it and the bad hire infects the organization for an extended
period before you figure out how to remove them. Engineering goals are
more generally team goals, there can be lots of reasons code can ship
late, and performance criteria are more subjective than sales
performance criteria. The mediocre hire ends up becoming part of the
team and it just ends up taking longer to fire that person on the team,
by which point they’ve added more subpar work to the mix. So, I am a
subscriber, outside of sales, to the thesis that you have to interview
rigorously and that it’s better to leave an urgently needed role empty
than to bring in a "false positive" who will infect the organization.