The following article was published in the Los Angeles Daily News on Thursday, 1 November 2001.

LAPD polygraph test results don't tell full truth

By George W. Maschke

LOS Angeles has awarded a $615,000 noncompetitive contract to a company to give polygraph tests to Los Angeles Police Department recruits, paying double the going rate for lie-detector experts.

Phyllis Lynes, assistant general manager for the Personnel Department's Public Safety Bureau, has defended the contract, saying, "The other alternative was not to staff the Police Department, and that's not an acceptable alternative."

A better alternative is to scrap the polygraph altogether.

Since February, when polygraph testing began, the LAPD has branded roughly half of the otherwise qualified applicants polygraphed as liars.

I have heard from numerous LAPD applicants who claim they were falsely accused of deception. One writes, "Here I was, thinking I was well on my way to serving LAPD with integrity and honor, being accused of not only being a druggie, but a liar as well."

Another notes, "I was told that if I tell the truth I have nothing to worry about; boy, was I wrong."

Those falsely accused of deception have little or no avenue of appeal.

Polygraph testing is no science. It depends instead on trickery. The polygrapher, while admonishing the examinee to answer all questions truthfully, secretly assumes that denials in response to certain questions -- called "control" questions -- will be untrue, or that the examinee will at least have doubts.

One commonly used control question is, "Did you ever lie to a supervisor?" The polygrapher steers the examinee into a denial by suggesting that anyone who would lie to a supervisor is unsuitable for hire.

The polygrapher scores the test by comparing physiological reactions to these probable-lie control questions with reactions to relevant questions such as, "Have you ever used an illegal drug?" If the former reactions are greater, the examinee passes; if the latter are greater, he fails. This simplistic methodology has not been validated by peer-reviewed scientific research.

Agencies value the polygraph because naive and gullible examinees sometimes make disqualifying admissions, saving the agency valuable time and resources.

But in the process, many truthful persons are being wrongly accused.

Perversely, the test is biased against the very straight-arrows the LAPD needs because the more honestly one answers the control questions, and as a consequence feels less stress when answering them, the more likely one is to fail.

Conversely, liars can beat the test by covertly augmenting their physiological reactions to the control questions. This can be done by constricting the anal sphincter muscle, biting the side of the tongue, or merely thinking exciting thoughts. Detailed information on countermeasures (methods for defeating the polygraph) may be found on the Web site

While polygraphers claim that any experienced examiner can easily detect countermeasures, peer-reviewed research has shown that they cannot.

Indeed, the American Polygraph Association quarterly has not published a single article explaining how to reliably detect polygraph countermeasures.

Nobody wants a repeat of the Rampart corruption incident. But pseudoscientific polygraph tests that are biased against the truthful yet easily defeated by liars are not the answer.

Instead, LAPD should scrap the polygraph and devote more resources to genuine background investigations.