Implicit Association Test
Also called IAT, D score, implicit attitudes
A timed sorting task that measures how much faster people pair two concepts with one attribute than the other, scored as a D score.
Words from four categories (two concepts, such as flowers and insects, and two attributes, such as pleasant and unpleasant) are sorted with two keys as fast as possible. In some blocks a concept shares a key with one attribute, in others with the opposite one. People are faster when the pairing matches an association they hold, and the difference in speed is the measure.
The improved D algorithm (Greenwald, Nosek and Banaji, 2003) uses the four combined blocks, drops trials over ten seconds, excludes people with more than a tenth of responses under 300 ms, and divides each difference in mean latency by the pooled standard deviation. By convention, |D| of .15, .35 and .65 mark slight, moderate and strong associations.
The order of the pairings is counterbalanced across people, because whichever comes second is a little slower for everyone.
Where it goes wrong
Reading one score as a verdict on one person. A D score is noisy at the individual level; it describes associations in a group, and should be reported that way.