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Are Polygraph Results Admissible in Court?

You have seen them on countless television shows, in movies, and heard about them being used in criminal investigations in a variety of cases. Polygraph machines, also known as lie detector tests, are a common trope in courtroom dramas and for many individuals, part of their mental image of a criminal investigation. But in a significant number of states, polygraph results are not admissible in court. In Florida, they can be admissible in court only if both parties involved in a case agree to use the results as evidence. In federal court, polygraph results are not admissible.

How Does a Polygraph Work?

When you take a polygraph test, you are connected to the test via sensors on your chest and fingertips. Although you might be familiar with the image of a polygraph pen wildly scratching results across a paper as the subject answers questions, today’s tests are generally conducted with computerized systems.

The test begins with an explanation of how the questions are worded and how the test works. Then, you are asked to answer a few test questions, such as your name, your age, and your current hometown. These are to create a set of “control” questions to be compared with the “relevant” questions, which are questions about the criminal investigation. Questions could be direct, asking about whether you committed the criminal offense, or they could be about your “guilty knowledge,” which is knowledge of the offense that only the guilty party would know. For example, a question of this type might have the subject answer about how much money was stolen in a multiple choice format.

Why Polygraph Results are Not Admissible in Court

Polygraph results are generally not admissible in court because they are not reliable. Polygraphs record the physiological changes that occur when the test subject is lying, such as a heightened heart rate, increased sweating, and changed breathing patterns. The problem with using these measures is that these changes can occur regardless of whether an individual is lying. Conversely, an individual could lie and not experience these changes.

Should I Take a Polygraph Test?

If you are asked to take a polygraph test, decline it. Even if you are innocent of your charge, there is nothing to be gained by passing a polygraph and much to lose if your test results indicate that you were not honest with your answers. In Florida, the only individuals who are required to take polygraphs are those on the sex offender registry who must take one annually, and even these test results are not admissible in court and instead exist solely to be used during the individual’s therapy sessions.

Work with an Experienced Miami Criminal Defense Attorney

If you are facing a criminal investigation, you need to work with an experienced Miami criminal defense attorney who can determine the best way to defend your case. A strong criminal defense strategy can mean the difference between having your charge downgraded or dismissed or being convicted and facing the penalties for that conviction. Contact our firm today to speak with an experienced member of our team at Ratzan & Faccidomo, LLC during your free legal consultation.

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