Polygraph testing has been shown to be very accurate – with between 85% and 95% correct results – but errors do sometimes occur. There are many reasons why this can be the case, such as failure to properly prepare the test subject for the exam, improper question formulation, or a misreading of the physiological data on the polygraph charts.
When an error occurs, it is called either a “false positive” or a “false negative.” A false positive means that a truthful test subject is reported as deceptive, and a false negative means that a deceptive test subject is reported as truthful.
It is very unlikely for a test subject to change a result from “deceptive” to “truthful,” and most attempts to deceive an exam will result in an inconclusive result. The best way to ensure that your exam is accurate is to disclose any psychological or physical conditions you have. The examiner will be aware if it is possible for the condition to affect the results and can take it in account when administering the test.
Examiners recognize that any error can be damaging, so they are trained to look for attempts to control breathing or heart rate, impairment due to drugs or alcohol, or other factors that may affect results upon meeting the subject and during the pre-test. Additional protective procedures that are taken to ensure an unbiased exam include:
- an assessment of the examinee’s emotional state
- medical information about the examinee’s physical condition
- specialized tests to identify the overly responsive examinee and to calm the overly nervous
- control questions to evaluate the examinee’s response capabilities
- factual analysis of the case information
- a pre-test interview and detailed review of the questions
- quality control reviews
If you believe that an incorrect reading was given, you have recourse. First, you can request a second examination be made or retain a different examiner to get a second opinion. You can also file a complaint with the state licensing board (if your state has one) and a complaint with the Department of Labor under EPPA. Additionally, if the polygraph examiner is a member of the American Polygraph Association, you can request the assistance of the organization.