Passkey Investigative Services

A polygraph examination is a procedure that measures and records several autonomic physiological responses — that are independent from our conscious control — while a person answers a series of questions. The underlying principle is that deceptive answers produce physiological reactions that differ measurably from truthful ones. A trained examiner analyzes the recorded data to reach a conclusion about the truthfulness of the examinee’s responses.

Research and field studies generally place the accuracy of polygraph examinations conducted by trained, certified examiners at between 85% and 95%, depending on the examination technique used and the skill of the examiner. Polygraph is not infallible, which is why professional examiners follow strict standardized procedures and why results are typically considered alongside other information rather than in isolation. The American Polygraph Association maintains ongoing research into examination validity and continues to refine best practices accordingly.

There are several types of polygraph examinations in use today, each of which can use a variety of formats. The three primary types are: specific issue tests, which are typically used for criminal questions; screening tests, which can test multiple topics and are used for pre-employment or general knowledge; and specified or hybrid tests, such as the post-conviction sexual offender test. The appropriate format within each type depends on the purpose of the examination and is determined by the examiner.