Accuracy of Polygraph

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Accuracy of Polygraph

What is the accuracy of polygraph? This is an important question and I want to congratulate you on making the extra effort to finding the answer. This blog can be useful for the person considering their first polygraph or for the professional providing services to their client. Therefore, we want to reveal the data and provide some things to consider before taking a polygraph.

Testing Topic

The testing topic is the first thing to consider. What are you trying to get verified? This is important because polygraph examinations are typically either single-issue or multiple issue. Both types of tests have pros and cons, so it’s important to determine the testing topic before scheduling your examination.


Single-Issue polygraph examinations are tests involving a single issue. They are Diagnostic Tests. For example, robbing a bank. If someone is accused of robbing a bank they can be tested on that single issue. Also, the test can be multi-facet such as planning or aiding.

The published data shows that the highest accuracy involves tests that are single-issue. The down side is you can only test on one issue at a time. If someone wants more than one issue verified, they have to undergo additional testing.

Single-Issue tests are typically deception tests. It’s important remember that multiple relevant issues in a single test deceases the accuracy of polygraph. Data does show that a single-issue exam can have an average accuracy of 92%, with the highest at 97%.

Multiple Issue

Multiple issue exams involve multiple relevant issues. This is not a deception test. They are commonly referred as screening tests, which involve no known issue or allegation.

These types of exams can be useful in treatment and/or supervision. It can serve as a decision making tool to support professionals in the field. Data for multiple issue test can have an average accuracy of 85%, with the highest at 93%


In conclusion, polygraph testing can be useful for a variety of reasons. They both have pros and cons, but deciding on the testing topic can assist in determining the accuracy of polygraph. A lot of people hire a private examiner and the examinee has a list of 50 items to be tested. This simply can’t be done in one test; therefore, the best advise is to pick the issue of highest priority.