The normally careful Association for Psychological Science has a piece on its website about the Implicit Association Test. Buried in the article is in article is this short paragraph:
Opinions on the IAT are mixed. Controversy about the test was evident in a 2013 meta-analysis by APS Fellows Fred Oswald and Phillip E. Tetlock and colleagues. They found weaker correlations between IAT scores and discriminatory behavior compared with what Greenwald, Banaji, and their colleagues found in a 2009 meta-analysis.
So there’s a debate about the validity (and the reliability, for that matter) of the IAT. But let’s not allow that pesky fact get in the way of hyping this instrument!
Here is an account of the problems with the IAT.
peakmemory 
Very interesting.