A polygraph test should not be shorter than 90min and in most cases will be longer. If a polygraph test is shorter than 90min, not all the relevant sections would have been followed according to the APA’s policies and procedures and the results can be questionable.

A number of factors impact on the accuracy of the polygraph test. The most important issue is ensuring that you use the services of a qualified and experienced polygraph examiner.

Objective research by the American Polygraph Association has established that, provided a polygraph test is conducted by an experienced and properly qualified examiner, the results should be 89% - 95% accurate depending on the testing technique.

The polygraph test is a really effective tool to help you in your decision-making process. When taken with all the remaining available facts, the test results can assist you in reaching the best-informed conclusions.

The most important is to select an examiner who is a full member of the American Polygraph Association.

Have at least 5 years’ experience as a polygraph examiner and has attended an internship.

Have a relevant Baccalaureate Degree e.g. Psychology, Criminology, etc.

The polygraph examiner must have experience and be willing to testify as an expert witness.

The polygraph examination measures changes in your body that take place when you lie. These changes are principally controlled by the automated nervous system. This makes them more difficult to affect consciously, which therefore increases the accuracy of the polygraph test.

The physiological reactions that are measured are changes in your electro dermal activity (sweat level), heart rate, blood pressure, breathing volume and breathing rate.

The more relevant question is “Can you beat the polygraph examiner?” People have been trying to beat the lie detector test since it was implemented, including famous cases of CIA operatives returning from the USSR who have been compromised. Numerous methodologies can be adopted as counter measures to try and pass a test while being deceptive. A skilled examiner who is alert to these activities will let a deceiving examinee know that their behaviour will result in them not passing the lie detector test.

Our empathetic polygraph examiner will certainly put the examinee at ease, but most examinees will understandably be nervous. It is normal to be nervous for two reasons. For most people it will be the first time they’re taking the test, which naturally makes this a more stressful situation. The second reason is that the outcome of a polygraph test normally has significant consequences. It is therefore normal that an examinee with this cognitive load – or concern about the consequences – will be apprehensive about the outcome. This does not have an impact on the result of the examination, but just changes the baseline measurements. It might be that an examinee’s normal resting heart rate is 60 beats per minute but, because they are nervously starting an examination, the rate has increased to 80 beats per minute. The results of the examination are based on the difference in physiological reactions to consecutive “relevant and comparison” questions. The fact that the base rate has changed from 60 to 80 does therefore have no impact upon these results.