Benjamin Todd

It's a meta-analysis of selection tests used by employers, drawing on hundreds of studies performed over 100 years.

Here are some of the results.

Here's a table with types of selection tests and correlation with job performance as an R-value.

IQ tests 0.65, interviews structured 0.58, interviews unstructured 0.58, peer ratings 0.49, job knowledge tests 0.48, integrity tests 0.46, job tryout procedure 0.44, GPA 0.34, work sample tests 0.33, Holland type match 0.31,

job experience in years 0.16, years of education 0.10, graphology 0.02, and age 0.00.

Almost all of these tests are fairly bad.

A correlation of 0.6 is pretty weak, and the accuracy for longer-term predictions is probably even worse.

So even if you try to predict using the best available techniques, you're going to be wrong much of the time.

Candidates that look bad will often turn out good and vice versa.

Anyone who's hired people before will tell you that's exactly what happens.

There is some systematic evidence for this.

And because hiring is so expensive, employers really want to pick the best candidates.

They also know exactly what the job requires.

If even they find it really hard to figure out in advance who's going to perform best, you probably don't have much chance.

If you were to try to predict performance in advance, going with your gut isn't the best way to do it.

Research in the science of decision-making collected over several decades shows that intuitive decision-making only works in certain circumstances.

For instance, your gut instinct can tell you very rapidly if someone is angry with you.

This is because our brain is biologically wired to rapidly warn us when in danger and to fit in socially.

Your gut can also be amazingly accurate when trained.

Chess masters have an astonishingly good intuition for the best moves.