On the interpretation of below-chance responding in forced-choice tests.

Two-alternative, forced-choice tests are commonly used to assess cooperation in examinations of neurocognitive functioning. Most commercially available tests do not primarily depend on comparing the total correct responses to the number expected by guessing. Nevertheless, the tests afford an opportunity to make stronger judgments about the cooperation of test-takers when the test score is lower than the range of scores expected for guessing. Unfortunately, many researchers and clinicians make serious errors in communicating what is "guessing" and what is "worse than guessing" (or malingering). This article describes proper methods of evaluating total correct responses on a forced-choice test.