Are polygraph exams accurate?
Many believe polygraph machines are a useful tool in finding the truth. Certain high level security government jobs and even local police department jobs require applicants to pass a polygraph exam. That being said the test is not infallible. There are ways to prepare for and attempt to “trick” the machine. Medication can affect the results of a test. The polygraph machine is simply monitoring body changes such as your respiratory rate, pulse rate, blood pressure, and sweat on your fingers as you answer questions. Some polygraph machines also measure arm and leg movement. The initial answers to questions such as what is your name and address are used to create a baseline to compare your psychological body reaction to the real questions.
How do police use polygraph exams?
If the police are asking you to take a polygraph test they generally believe you are guilty. They are not trying to clear you as they may proclaim (police are allowed to lie), but instead are gathering evidence to use against you at trial. Even though the results of a polygraph exam are not admissible in Court your answers can be used against you in Court. Generally speaking you never want to talk to police without a lawyer present. Many lawyers won’t let their clients be questioned under any circumstances. Your statements only lock you into a timeline or story and any inconsistent statement may be interpreted as evidence of your guilt.
If I pass a lie detector will the case be dismissed?
Even if you pass a lie detector test, that does not mean you will not be charged or any charges already brought will be dropped. Once again, the results are not admissible because the science behind lie detectors is not foolproof. Even if you pass the polygraph exam, law enforcement may just assume you are a good liar.
What If I want to take a polygraph exam?
If you really want to take a polygraph exam, then you may consider coordinating with your lawyer to hire your own examiner and pre-screening the questions. That way if you “pass” your attorney can take the results to law enforcement or the District Attorney. That being said, law enforcement generally will request you sit with their examiner where they can ask unknown questions and essentially interrogate you.