Edouard Machery (Pittsburgh), a leading scholar working at the intersection of philosophy and psychology, gives a useful assessment:
The history of attitude measurement in psychology is one of exuberant, irrational enthusiasm followed by disappointment when the shortcomings of the new indirect measures come to light.
The recent history of the implicit association test is just the most recent episode in this sad history of irrational exuberance followed by disappointment. We were told that the IAT measures a novel type of attitude—mental states that are both unconscious and beyond intentional control, which we’ve come to know as “implicit attitudes”—and that people’s explicit and implicit attitudes can diverge dramatically: As we’ve been told dozens of times, the racial egalitarian can be implicitly racist, and the sexist egalitarian can implicitly be a sexist pig! And law enforcement agencies, deans and provosts at universities, pundits, and philosophers concerned with the sad gender and racial distribution of philosophy have swallowed this story.
But then we’ve learned that people aren’t really unaware of whatever it is that the IAT measures. So, whatever it is that the IAT measures isn’t really unconscious. And we’ve learned that the IAT predicts very little proportion of variance. In particular, only a tiny proportion of biased behavior correlates with IAT scores. We have also learned that your IAT score today will be quite different from your IAT score tomorrow. And it is now clear that there is precious little, perhaps no, evidence that whatever it is that the IAT measures causes biased behavior. So, we have a measure of attitude that is not reliable, does not predict behavior well, may not measure anything causally relevant, and does not give us access to the unconscious causes of human behavior. It would be irresponsible to put much stock in it and to build theoretical castles on such quicksand.
Lesson: Those who ignore the history of psychology are bound to repeat its mistakes.
There are other commentaries at the same site, though Machery's stood out for cutting to the chase.