The CQT was developed to address flaws in the “relevant-irrelevant” polygraph technique, which involves comparing the subject’s response to crime-relevant questions with irrelevant question on topics for which the correct answer is readily apparent. This technique is seldom used in forensic settings because even innocent people are more physiologically reactive to the threatening accusation contained in the relevant question compared with the response to the irrelevant question. The CQT was developed to address this flaw by replacing the irrelevant query with a comparison question. Traditionally referred to as the “control” question, this question is also accusatory, but it does not deal with the crime at issue. Instead, it probes the integrity of a subject by asking about possible past misbehavior that a person who committed the crime at issue might also have committed. In using the control question, the test assumes that the control questions are likely to elicit lies or at least nervous denials. CQT proponents argue that because the control questions are the only questions for which the innocent subject has any reason to be concerned, truthful people will respond more strongly to the control than to the relevant question. By contrast, liars are expected to find the relevant questions of greater concern, so they should respond more strongly to these questions. This article argues that the CQT has a weak theoretical foundation, is biased against the innocent, and may be subject to countermeasures by the guilty to appear truthful. Thus, CQT results cannot constitute evidence of either deception or truthfulness. 37 references