Inconclusive Polygraph Results-Why?
By Dan Sosnowski

For police agencies that utilize the polygraph as an investigative tool, there is always that nagging question as to why was I informed that the suspect’s results were inconclusive. What does that term really mean? Does it mean that the suspect sort of told the truth and sort of told some lies? Can I eliminate him as a suspect? Is he leaning towards being deceptive or nondeceptive?

Well, the answers to those questions are “No”. Just because an individual’s test results were rendered as “Inconclusive” or “No Opinion” doesn’t mean that the individual is lying or telling the truth. In fact the examinee may be doing some of both. As an investigator, you must remember, the examinee knows whether or not they were involved in case that is under investigation. It is us who are not sure of their potential involvement. It is the examiner who conducted the test who is “Inconclusive”

There are several factors that could cause the results of a polygraph examination to be rendered as “Inconclusive”. Some of these factors include improper question formulation based on bad case facts. The lack of fear by the examinee of getting caught in a lie is sometimes a reason for this result. The issue of little or no consequences is another contributing factor that has to be addressed. It is the job of the examiner to establish the proper psychological set for the polygraph examination. It is also the job of the examiner to determine what the best questions for that particular test are. Questions that are compound or ambiguous often create confusion in the mind of the examinee as to which part of that question pose the most danger to their overall well being.

In order to avoid “Inconclusive” test results, the examiner must understand the case facts in order to develop the best possible questions for this exam. But when all is said and done, there is still the possibility of the test being rendered as “Inconclusive”. This opinion is generally rendered in about 6-10% of cases however when a second test is administered, and examiner is able to render an opinion of No Deception Indicated or Deception Indicated in about 90% of those cases.

In conclusion, if you will be using the polygraph instrument as an investigative tool, provide your examiner with all of the possible data available. Inform your examiner so that in return, they can assist and inform you.

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For the Public Agency Training Council, Dan instructs the following courses:

Interviewing the Sexual Deviant

Kinesic Interview & Interrogation Phase I

Kinesic Interview & Interrogation Phase II

Find any of Dan's classes that are currently scheduled at the PATC Training Schedule