Polygraphs Accurate But Not Foolproof

July 14 -- Rep. Gary Condit believes the independent polygraph exam he passed proves he was not involved in the disappearance of missing intern Chandra Levy. But while often accurate, polygraphs are not foolproof, experts say.

"Proponents will say the test is about 90 percent accurate. Critics will say it's about 70 percent accurate," said Frank Horvath of the American Polygraph Association. "Many people refer to polygraph tests as lie detector tests, and that's a bit of a misnomer.

"There is no test that can detect lies. … The process in which the questions are asked and the sequence of the questions may affect how a person reacts," Horvath said. "Since the process is not perfect, that could lead to the possibility of error, and that's why there's problems when trying to get them in the courts."

Polygraph literally means "many writings" and it refers to ways in which several physiological activities are simultaneously recorded during a test. During a standard polygraph test, examiners monitor at least three bodily reactions to determine whether a person is truthfully answering questions: respiratory rate, sweat gland activity, and cardiovascular activity.

Condit Test Done Independently

Condit's attorney, Abbe Lowell, announced that the California congressman had passed an independent exam given by Barry Colvert, a former 35-year veteran FBI polygraph examiner, and not investigators involved in the case. Lowell said the test showed "no deception" by Condit.

But Washington, D.C., police called the test Condit took "self-serving" because authorities did not take part and had not seen the full results. "We'll take thatinformation like we take everything, and examine it," said Assistant Chief of Police Terrance Gainer.

Levy has been missing since May 1, and her parents had called on Condit to take a polygraph. The congressman has admitted to police that he had an affair with the young woman, according to sources.

But Levy attorney Billy Martin said the missing intern's parents were "very disappointed" about the privately administered polygraph. "We're wanting him to be fully cooperative and not cooperate on his terms," Martin told reporters.