Raymond,

Whether one chooses to refer to it as "lie detection," "truth verification," "polygraph," "psychophysiological detection of deception," or the latest buzzword, "credibility assessment," at its core, polygraph "testing" purports to determine whether a person has spoken the truth (as nopolycop and Sergeant1107 correctly stated). When I failed my FBI pre-employment polygraph (despite having answered all relevant questions truthfully), my polygrapher reported "It is the opinion of this examiner that the applicant was deceptive when responding to the listed relevant questions in Series I and Series II," and my file was summarily marked "no action - polygraph deceptive." There was no mention of whether my reactions were a "good or poor fit" for some supposed "model."