Police Polygraph Test


The polygraph was never developed, or intended, for law enforcement; although, its use in law enforcement has become widespread.

Detective Lieutenant Barry M. Baker (ret.) is a 32 year veteran of the Baltimore Police Department.

The police polygraph test can be part of a hiring process, but it’s usually reserved to clear issues raised by the background investigation. The worst thing about a police polygraph test is the pre-test anxiety it produces. There’s a reason why the results of a police polygraph test used in a criminal investigation cannot be admitted as evidence in any court proceeding.

The police polygraph test is simply not reliable. A young police officer once applied for reassignment to a vice unit in a major police department. A police polygraph test was required, and it was administered by the department’s full time polygraph examiner. The examiner had twenty years’ experience, and he was considered to be a highly qualified expert in his field.

After a pretest interview, the examination began. Nearly every question during the police polygraph test revolved around the officer’s marriage. “Have you ever cheated on your wife?” “Have you ever lied to your wife?” “Did you ever hold back money from your wife?” The officer answered no to every question.

The examiner stopped the questioning for several minutes as he wrote hurriedly on a note pad. As the officer sat waiting for the examiner to continue, he turned his head toward the machine. The officer was curious to see a reaction from the machine, so he took a sudden deep breath. He wanted to see if the needles on the machine would react. The sudden wide swing of one of the needles caught the examiner’s eye and elicited a rebuke. “Stop fooling around, and look straight ahead.”

Marriage; Money; Lies and Sex – Food for the Police Polygraph Test

The examiner resumed the testing, and he continued to focus on the officer’s marriage. He asked the same questions again, but he asked them with different variations. “Have you ever had an affair during your marriage?” “Have you ever had sex with another woman during your marriage?” The questions about money were similarly varied.

After exhausting the subject of marriage, money, lies, and sex, the examiner abruptly concluded the police polygraph test. The officer asked if he’d passed the examination, but the examiner would not share his professional conclusion with the officer. You see… that’s part of the police polygraph test mystique. They’ll never tell you if you pass or fail.

The officer left the examiner’s office feeling pretty good about the test. The examiner didn’t have to tell him he’d passed, because he’d answered every question truthfully.

The questions were valid for a police polygraph test since an assignment to vice enforcement would constantly expose the officer to sex and money. However, the examiner made one critical mistake during the pretest interview. He verified that the officer was married, but he never inquired as to how long the officer had been married.

In this case, I’d only been married for two short weeks. Had the examiner known that fact, his questions would have been much different.

Perhaps you’re wondering if I got the assignment? You’ll learn that it takes a lot more than truthfulness to get an assignment of your choice.

It’s Just a Machine

A polygraph is just a machine. “During a polygraph, an examiner is always paying attention to these fundamental clues and cues, developing a sense of the suspect’s values, beliefs, motives, and attitudes.” Talk about everything being in the eye of the beholder. It doesn’t sound much different from what you’ll be doing every time you interrogate a suspect.

The polygraph was never developed, or intended, for law enforcement; although, its use in law enforcement has become widespread. Oh, well, that’s cops for you – always looking for a shortcut.

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