Differential item functioning (DIF) is the tendency of a test question to be more difficult (or easy) for certain specified groups of test takers, after controlling for the overall ability of the groups. It is possible to perform a DIF analysis for any two groups of test takers, but the groups of test takers ETS is particularly concerned about are [..]

An item exhibits differential item functioning if the probability of doing well on the item depends on group membership, even after controlling for overall performance.

An item exhibits differential item functioning if the probability of doing well on the item depends on group membership, even after controlling for overall performance.

A statistical characteristic of an item that shows the extent to which the item might be measuring different abilities for members of separate subgroups. Average item scores for subgroups having the same overall score on the test are compared to determine whether the item is measuring in essentially the same way for all subgroups. The presence of D [..]

Item bias as a result of systematic differences in responses across cultures due to features of the item or measure itself, such as poor translation or ambiguous wording.