Major categories of factors that affect the accuracy level of the polygraph are the examiner, the examinee, the investigation, and the examination conditions. Quality control reviews may also be useful in the assessment of polygraph results. An examiner should have been trained at a reputable polygraph school or through a course accredited by the American Polygraph Association. The training should not place primary emphasis on an examinee's behavior and body language. The best examiners will be proficient in at least one and probably a variety of recognized polygraph techniques that have been proven to have a high level of validity. Accuracy factors related to the examinees are their physical and emotional conditions. Those in poor health or who are under severe emotional stress are poor candidates for examination. Another set of accuracy factors is related to the investigation. Unless the examiner is supplied with reliable investigative input as a foundation for the examination, the results are likely to be flawed. Examination conditions also affect polygraph reliability. Sufficient preparatory time and a facility controlled for comfort and privacy without interruptions are crucial to the production of a reliable outcome. 7 footnotes