5 Reasons a Polygraph Test May Not be Accurate

First and foremost, never talk to the police until after you have consulted with a criminal defense lawyer. There is a very good reason the cops must tell you…you have the right to remain SILENT, anything you say can and WILL be used against you…. Many Missouri criminal cases and won and lost based on what the police claim you said when you were questioned or arrested. They are not your friend, if you tell them what they want to know they will not be nice and let you go, they will charge with a crime if they can. With that being said, I think it is obvious never to take a polygraph test either. Below is a guest article about polygraph tests:

Continuing controversy surrounds the validity of polygraph testing, especially when results are used to make important determinations about employment, legal responsibility and criminal guilt. While the platform furnishes a viable tool for law enforcement agencies and others who screen job candidates and suspected criminals, detractors point to the limited reliability of such tests.

While the technology is increasingly used to screen candidates for federal employment, and to pursue criminals, some scientists believe – flat out; polygraph tests are ineffective for determining whether or not a subject is telling the truth. But that doesn’t make lie detector tests worthless in the pursuit of truth. Their most useful function, according to some, is creating accountability among subjects who believe in the efficacy of polygraphs, prompting them to be more truthful during interviews and interrogations.

Wherever you fall on the spectrum of confidence, it is important to understand the way polygraphs work and recognize the role the technology plays in the legal system. Like other tools available, however, lie detector tests must be embraced with their limitations in mind, including a few reasons they may not be accurate.

Cause and Effect?

Lie detector tests provide feedback based on changes in bodily functions. Monitoring variables like blood pressure and heart rate; polygraph examinations rely on reading anxious reactions from the body’s systems. Unfortunately, it is difficult to isolate the causes of anxiety, which are not necessarily explained by a polygraph subject’s lies. Theoretically, anxiety related to extenuating circumstances may be construed as mistruths, leading to false polygraph results. In other cases, it may be possible for subjects to manage their emotions, even when lying, which also undermines the reliability of the tests.

Subjective Results

Technology is only as reliable as the human element controlling it, so lie detector tests are subject to the same limitations presented by other technical approaches. In fact, interpreting polygraph findings is not a universal science, so there is a great deal of subjective latitude inherently present in the procedure. As a result, false results emerge due to operator bias, rather than empirical evidence.

Guilty Knowledge Test

While polygraphs may not be sufficiently accurate to lean on them for prosecutions and excluding employment, the feedback they provide furnishes a useful component of comprehensive investigations. And since lie detector tests are not conducted according to a single standard, dialing-in the proper approach furnishes the most useful information. Guilty knowledge tests, for example, may provide the most accurate returns, though this method for administering tests is not always used. Instead of broad queries, the guilty knowledge approach instead focuses on specific bits of knowledge only a guilty party would know. By including multiple choice responses, lie detector administrators strive to illicit stand-out reactions to the proper answer. A break-in, for example, may be investigated using a series of multiple choice answers about how a home was breached. A subject responding to the correct answer in an anxious manner probably has a greater likelihood of being guilty than one who doesn’t. Reliability of polygraph results decreases when the wrong testing methods are used.

Conflict of Interest

Empirical findings yield the most useful conclusions within the legal system, because they are harder to refute than subjective returns. Too often, agencies conducting polygraph examinations have agendas of their own, prompting them to manipulate findings to support their own causes.

Pinocchio Response yet to be Identified

The entire premise of reliable polygraph testing stands on finding an irrefutable Pinocchio response within human physiology – wherein a lie undeniably causes the body to respond in a predictable way. Despite the widespread use of polygraph testing, and belief among the population that the technology works, there is no obvious metric available mimicking Pinocchio’s volatile growing nose.

Until science and technology furnish breakthroughs sufficient to bolster reliability and diminish bias, lie detector tests should be used within their limitations.


Daphne Holmes contributed this guest post. She is a writer from arrestrecords.com and you can reach her at daphneholmes9@gmail.com.