A large number of variables may influence polygraph accuracy. For appropriate use of polygraph results, knowledge of how these factors influence accuracy will permit better-informed judgements about the weight accorded to an examiner's opinion concerning the veracity of the examinee's statements. Categories of factors discussed are the examiner, the examinee, the investigation, and the examination conditions. Although research indicates accuracy levels exceeding 90 percent, this does not mean that 90 out of 100 examinations conducted by every examiner in every situation will be correct. Federal investigative and intelligence standards specify that examiner conclusions should not alone determine investigative fact nor used to exclude other evidence. Quality control reviews are important for promoting consistency and should be implemented locally or through FBI headquarters. References.