In an effort to appraise the effectiveness of deception in psychological research, published studies that used this tactic were reviewed. Few reported any information about subjects' suspicions of the deceptions, regardless of the studies' substantive area or the kinds of deceptions they employed. In the studies reporting such information, only a small percentage of subjects were suspicious irrespective of the studies' substantive area of deceptions. The inadequacy of the criteria employed for assessing suspicion and other possible sources of distortion in the reported rates of suspicion were discussed. The need for guidelines for evaluating deception studies and effective procedures for measuring subjects' suspicions was emphasized.