[jfim]

The amount of false negatives really depends on where the bar is for passing the interviews.

If the bar is "it looks alright and the person knows the language they're using," it's probably not generating a whole lot of false negatives. If the bar is "the candidate comes writes the optimal solution to a complex algorithmic problem in 45 minutes," then that's highly noisy and tends to filter for people who have done a very similar problem recently.

Unfortunately, too many interviewers use the latter bar for passing or failing candidates.