Are there some people who can beat a polygraph test?
Can drugs affect a polygraph test?
Are polygraph tests admissible in court?
Can a polygraph examiner manipulate a polygraph test to cause the subject to pass or fail a test?
If I’m accused of a crime, should I take a police polygraph examination?
 

Are there some people who can beat a polygraph test?
Yes. As with all diagnostic testing, there is always an error factor. The federal government has determined through past studies that the polygraph instrument is accurate up to 97% of the time. This leaves a 3% margin of error that various studies have indicated can be even greater or less than. Sociopathic personalities, such as unsavory used car salesmen or snake oil salesmen, have the ability to rationalize improper acts a lot better than most common citizens. Those individuals would have a greater possibility of being able to pass a polygraph examination, but it is most examiners’ experience that as long as the subject knows the difference between the truth and a lie, even sociopathic personalities will trigger enough response on a polygraph examination to fail if indeed they are lying. Psychotic individuals who do not understand reality are fortunately few and far between in this society, but those individuals may in fact show no reaction on a polygraph examination. Fortunately, both sociopathic and psychotic members of society are a very small percentage. Most people, once they understand the difference between the truth and a lie, are very good subjects for polygraph testing.

Can drugs affect a polygraph test?
Yes. Drugs can affect a polygraph test, but no matter what the drug these drugs usually react throughout the course of a test and a deviation from the mean average should in fact be detected even if the subject is using some recreational drugs. Polygraph examiners incorporate control tests prior to their polygraph examinations in most cases to determine if the subject is indeed testable. If there is a lack of response to control questions, that would be indicative that whatever medication the subject is on is going to neutralize the test, thus a test would not be conducted. So, detecting that will indeed discourage any false negative or false positive reactions on a polygraph test. In short, though drugs may affect a test, an examiner is going to cancel the test so the drugs are not going to help anyone to pass a polygraph examination. In fact, it will just call attention to the polygraph subject as to why they were taking recreational drugs in an effort to defeat the test.

Are polygraph tests admissible in court?
Recent court decisions have indicated throughout the country that polygraph examinations are not uniformly used in court for a myriad of reasons, one of which being that most subjects have a fifth amendment right and there is not a more obvious form of self-incrimination than taking a polygraph test, where one is actually testifying against himself if indeed he is lying. Most defense attorneys will not recommend taking a polygraph examination unless it is done privately for the defense attorney, in which the results of that test will not be made known to anyone if indeed the subject fails the polygraph examination. Of course if the subject passes the test, there will be few people in the jurisdiction of the defense attorney who will not be told that the subject passed the examination.

Can a polygraph examiner manipulate a polygraph test to cause the subject to pass or fail a test?
Yes. They can manipulate it, but review of the test by other polygraph examiners would easily detect that there had been manipulation on the polygraph test and thus make the examiner’s credibility and the test in question invalid. The high standards of the polygraph profession would rapidly sensor any future work done by the polygraph examiner. Credibility of the polygraph subject would indeed be ruined at that point, so it defeats the purpose of any manipulation attempts.

If I’m accused of a crime, should I take a police polygraph examination?
It is always recommended that if anyone is accused of a crime they seek counsel first and then at that point determine whether they are going to take their own private police polygraph examination through an examiner picked by the defense attorney prior to submitting the potential defendant to the police polygraph examiner. However, another effective way of monitoring a police polygraph is to request your examiner to be able to peer review the police polygraph examination and/or the video tape of the police polygraph examination. Most defense attorneys will opt to test the subject prior to submitting to law enforcement, just to make certain the polygraph subject’s claims of innocence are indeed true before he makes those statements to law enforcement.