Interview scores had no correlation with performance ?

Google has found that interview scores had no correlation with performance, of those who got hired. A few things to observe here:

• Some interviewers are harsher graders than others. A hiring committee can see that your 3.2 was a very good score from the guy who averages a 2.3 average score, but a mediocre score from the guy who averages a 3.0 average. The study likely doesn’t take this into account.
• The interview score is merely a quantitative measure of your performance, but it’s not the whole picture of your performance. It’s possible that your qualitative interview performance (you know, all those words your interviewer says about you) is quite correlated with job performance, but the quantitative measure is less correlated. The people actually deciding to hire you or not are judging you based on the qualitative measure.
• People who are hired basically all have average scores in a very small range. I would suspect 90% of hired candidates have between a 3.1 to 3.3 average. Thus, when you say there’s no correlation between interview performance and job performance, we’re really saying that a 3.1 candidate doesn’t do much worse in their job than a 3.3 candidate. That’s a tiny range.
• Perhaps most importantly, the study is only looking at people who were hired. It’s not looking at people at random. This doesn’t mean that interviewing is broken. It just means that, once people hit a certain, very high bar, then it doesn’t matter whether someone gets above that or far above that.To make an analogy: suppose a study was done showing that people had the same life expectancy whether they worked out 7, 8, or 9 hours a week. Would it be fair to conclude that working out doesn’t affect your life expectancy? Of course not.
• The thing about “some of their best-performing employees had horrible job interview ratings” is much less interesting than it sounds. It’s true that Google found some correlation between a candidate who did terrible (< 2.0 out of 4.0) in one interview and a strong job performance. Why would that be?Because if a candidate gets below a 2.0 in one interview, but still gets hired, there must have been something else to counteract it. Maybe it was an amazing background. Maybe it was other interviewers fighting for them.On top of that, the lowball score was also probably a bad interviewer. Below a 2.0 is really quite low. You have to really screw up to do that. If a candidate gets below a 2.0 in one interview, and above a 3.0 in the others, the candidate probably got a stupid interviewer (“This candidate [who has never worked with C or C++] didn’t know pointers! Fool! I would never hire someone like that!”).
• The better way to see this fact is this: candidates who overcame a terrible interview to still get hired tended to do well at the job. Not so shocking, is it? In fact, it’s almost an endorsement for the interview process.

The way that Google looked at job performance suffers from basically all of these same problems. Job performance was also based on quantitative measures. And of course it was; how else would you look for a correlation?

Chosen excerpts by Job Market Monitor

via Is There A Link Between Job Interview Performance And Job Performance? – Forbes.