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Taking the Mystery Out of the Polygraph Test

Taking the Mystery Out of the Polygraph Test

Sergeant Betsy Brantner Smith

A polygraph exam is often a “make or break” part of the police testing process, but it’s often difficult to prepare for and even understand. As Richard Nixon said “I don’t know anything about lie detectors other than they scare the hell out of people!” Polygraph testing is used far more in government pre-employment processes than in the private sector. In recognition of this, the APA Research Center at Michigan State University surveyed 699 police executives from some of the largest police agencies in the United States to determine the extent of, and conditions in which, polygraph testing is being used for pre-employment screening (this survey excluded federal agencies). The major results of the survey showed that of the respondents 62% had an active polygraph screening program, 31% did not and 7% had discontinued polygraph screening. Admittedly, polygraphy is not an exact science, but if it’s going to be a part of your next law enforcement employment process, take the time to learn the basics.

The polygraph, or “lie detector” is an instrument that measures and records physiological responses like breathing rate, pulse, blood pressure and perspiration. The underlying theory of the polygraph is that when people lie they get measurably nervous about lying. Its name stems from “poly” for the multiple sensors used and “graph” for a single strip of moving paper that records information, although most polygraph examiners now use computer images instead of analog instrumentation. A polygraph examiner is generally a highly trained interrogator as well as the technical operator of the devise and will use their experience in addition to the machine to detect your truthfulness.

One of the most intimidating parts of the polygraph exam is being attached to the sensors that will collect physiological data from at least three systems in the human body. After being attached to four to six sensors, your polygraph exam will likely start with a pre-test interview to gain some preliminary information which will later be used for control questions; this is called the “Control Question Test,” or CQT. Often, the examiner may ask you to deliberately lie several times to test your responses; this is a “Directed Lie Test,” the DLT. They may also ask “probable-lie” questions, such as “have you ever stolen anything?” (even the most honest person has “stolen” a pen from work or a candy bar from their little sister or some other “theft” that concerns them enough to show a stress response when answering).

Finally, they may use the “Guilty Knowledge Test,” GKT, a test that compares physiological responses to multiple-choice type questions about particular facts that only the examiner and you would know. The majority of American Psychological Association members surveyed think that the GKT is the most accurate of these tests and consider it “a promising forensic tool.” However, polygraph testing is still largely controversial in the U.S., so why do so many police agencies use it?

In the Michigan State survey the great majority of the agencies using polygraphs indicate that lie detectors reveal information that cannot be obtained by other selection methods. They also stated that polygraph testing makes it easier to establish background information, that it deters undesirable applicants, and that it is faster than other methods of selection. About half of the agencies using polygraph testing for sworn positions also use it for non-sworn employment, such as dispatchers, records clerks, and even secretarial personnel.

CIA operative-turned-spy Aldrich Ames, convicted in 1994 of spying for the Soviet Union, famously passed several lie detector tests by allegedly being told by his Soviet handler to "Get a good night’s sleep, and rest, and go into the test rested and relaxed. Be nice to the polygraph examiner, develop a rapport, and be cooperative and try to maintain your calm.” Often subjects are also told to try and control their breathing or artificially raise their heart rate during control questions (IE: thinking about a scary movie scene even while you are telling the truth), but the bottom line is this: tell the truth.

Come to your polygraph exam well-rested and well-fed, dress appropriately, and answer the questions truthfully to the best of your ability. Most police agencies don’t expect you have lead a perfect life, but they do expect you to be truthful. After all, law enforcement is profession of honor and integrity. Good luck.

  • Photo_user_blank_big


    almost 2 years ago


    Mike, in all the jobs that my son has applied for, the polygraph was in fact the deciding factor...and he was as honest with them as he could be...even told them he had problems with them...Yanno, what bothers me the most, is when people say, if you don't have anything to hide you will pass them easy, well, I think it is time, anyone who feels like that, understands, everyone is different, and there have been a whole lot of honest people disqualified from jobs b/c of a machine????? believe me, I've read some stories from FBI personal who have failed the test...and yes, not everyone tells the truth either...but, I believe there are cases, like my son. And I will say this, due to they're inaccuracy, they are not submissable in just doesn't make any sense? It makes me feel so bad for those like my son, who are honest, forth right who are disqualified due to this machine.

  • Photo_user_blank_big


    almost 2 years ago


    My son has been in law enforcement 14 years....and has a terrible time with poloygraphs...he gets so nervous beforehand, as he failed one years ago, once, and I will tell you this, my son does not lie, actually, I wish I could be more like him, due to his integrity, his laid back ways...he is fair, and always, looks at things objectively, and due to his refrences, would be an asset to any department, however, he just failed another polygraph and lost the job...and I will tell you, since he was a young boy, he always told the truth, no matter the consequences, or how hard it was. Some people do very well with them, others do not, and I will tell you this, if my son inherrited any bad from me, it would be this, b/c if someone accuses me of something, I become extremely nervous and even look guilty. We are all numb and disappointed, to add insult to injury, this last job he really wanted bad...and when he phoned me before leaving, I knew he was going to fail it, b/c he was so nervous about it...he is such a good man, and I feel so badly for any department that looses a good candidate to a machine...why don't they call any candidates refrences? I mean, his file is clean...not to mention, where ever he goes he makes friends. Two of his buddies said, I think the longer we are in this career, the more likely we will be to fail the polygraph, b/c of what we have seen, b/c the questions trigger a memory...which makes sense...

  • Stopsign_max50


    over 3 years ago


    The problem with the polygraph is that it gives to many false readings. However it is important to prepare yourself for the test so you can calm your nerves. One great website that does a great job in preparing you for the exam is ... I followed all the advice on that site, and the result was I pass the polygraph with flying colors. To be honest with you It's not as hard when you know all the questions in advance.

  • Swat_teaser_fin_sm001_max50


    over 3 years ago


    What about the CVSA?

  • 1282013_012_max50


    over 3 years ago


    I recently took my poly for the agency that I applied to. I passed and it was a breeze. Just as Top_Cat stated. All you have to do is tell the truth. Basically if you're worried about a polygraph, then, you pretty much are sending red flag signals because of a past event that might disqualify you. Just admit it to the examiner. You should have already admitted everything to your Background Investigator and if you did and you have not gotten DQ, and you actually made it to your polygraph, well then there is nothing to be worried about.
    Good luck to all that are getting ready to take their polygraph.

  • Photo_user_blank_big


    over 3 years ago


    I believe polygraphs as a condition of employment should be outlawed. Back in the 70's, all convenience stores required them as a condition of initial employment and for monthly follow-ups. Laws were made or doctrines established which eliminated these invasive procedures but unfortunately, police were exempted from these protections.

    Much of the stuff that people are asked is really none of the department's damned business and they have no right to expect an answer, much less an honest answer. Do a good background check on the applicant and use that as your criteria. Females in particular are targets of questions about their sex lives and again, things which are absolutely none of the department's or the examiner's damn business. My ex was asked numerous invasive questions by the examiner at the Sheriff's Department she joined. The examiner later was brought out in a scandal where he turned on a recorder in an interrogation room and videotaped a privileged conversation between a murder suspect and his attorney.

    I am happily retired now but would never consider employment where a polygraph was mandatory. There are too many ways these things can give false readings.

  • Puppy_max50


    almost 4 years ago


    ready to take one as soon as possible =] feel free to hire me now

  • Photo_user_banned_big


    almost 4 years ago


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  • Photo_00002_max50


    almost 4 years ago


    Make full disclosure, voluntarily, before taking the polygraph. Don't try to "beat the test". LTC Nugent

  • Mike_pinstripe_suit_max50


    almost 4 years ago


    First, polygraph exams are NEVER the only criteria used during the hiring process. It is merely one of the tools in the hiring process bag. As far as accuracy, polygraph exams (as documented in the latest University of Utah research) is 91% using standard testing formats. Most good examiners will also use another examiner, whom he does not know, as his Quality Control and to also score the examination. This increased the likelyhood of a fair test.

  • 030801-f-2751g-014_max50


    about 4 years ago


    This was very helpful thank you.

  • Photo_user_banned_big


    about 4 years ago


    Google "Quadri-Track ZCT"

  • Ronwestptjune2011_max50


    about 4 years ago


    It's illegal to use a polygraph as a condition for employment for any job (including Law Enforcement) in NJ. As a B/I, we just had to work that much smarter...

  • Photo_user_blank_big


    about 4 years ago


    Poly should not be the end all in the application process. It should be one tool in the hiring process and if something doesn't seem right with the answer, it should be passed along to the background investigator to be vetted. I never understood how someone could pass a test at one agency and then fail at another or fail then pass a test at the same agency. Makes me question how reliably they are, but for most, if you fail, your out.

  • Mark_twain_and_me_max50


    over 4 years ago


    Aldrich Ames and Robert Phillip Hanssen both passed polygraph exams while they were actively spying against the United States. It can help a backgound investigator to focus their investigative efforts, but that is about it.

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