Polygraph Testing - When Can It Be Used?
It depends on the reason that the test is being proposed.
Most states ban the polygraph as evidence of guilt or innocence in criminal trials. Polygraphs are considered unreliable for this purpose. Juries, according to the courts, should not rely on the polygraph in considering witness credibility. So, in the 1979 case of State v. French, which is still the law in New Hampshire, it was held to be error to even refer to these tests.
In fact, where prosecutors asked whether a witness took a polygraph test the case was reversed. The New Hampshire Supreme Court held that a prosecutor was attempting to bolster the credibility of one witness by referring to his having taken a polygraph. The allowance of the question was held to be error, and the case was reversed and sent down for a new trial. (State v. Ober, 1985.)
However, the polygraph is not entirely dead as an investigative tool.
Polygraph testing is still accepted as a useful tool in internal investigations of police misconduct. That issue was presented to the New Hampshire Supreme Court. The court followed rulings in Ohio, Connecticut and California. In the Ohio case, a police dispatcher refused to obey an order to take a polygraph, and the refusal was found to be just cause for the officer's dismissal.
Florida Courts disagree, holding that the possible investigative benefit of building a case on lie detector tests is too weak to support a denial of a police officer's right to be subjected only to lawful and reasonable orders.
The Federal Employee Polygraph Protection Act prohibits many private sector employers from using polygraph tests for pre-employment screening or during the course of employment. However, the same law, updated in the year 2000, recognizes that the polygraph may be useful for some purposes. The federal act contains a limited exemption for ongoing investigations provided certain conditions are met, as well as an exemption for private employers whose primary business consists of providing security. 29 United States Code, Section 2006.
So the bottom line here is that private employers in large part should not subject prospective employees to a lie detector, but one exception includes security based jobs.
Status of the polygraph in New Hampshire outside of the criminal courtroom is on a case by case basis. For example, a psychologist who faced a complaint at the board of examiners was so sure he was right that he wanted to introduce the results of a polygraph test that he took. The case went up on appeal, where New Hampshire's rule of inadmissibility in criminal proceedings was noted. The court said the rule is based on the "dubious scientific value" of the polygraph. Many states exclude the results of polygraph examinations from administrative proceedings. So, the New Hampshire administrative board was upheld in excluding the polygraph examination.
Polygraphs date back to the early 1900's. That was before Wilbur and Orville Wright flew a plane and before even black and white TV. Last time I heard, even last year's computer was bound for the recycle center. And, skilled interviewers including attorneys doing cross examination, seasoned police detectives and others have a way of cutting through the smoke to identify the truth. Lie detectors should not be used unless a specific law or contract requires it. Even then, it wouldn't hurt to ask questions first.