Even if it isn’t 100% accurate, the polygraph test can be a valuable tool to determine a suspect’s guilt or innocence when considered alongside other forms of evidence.
Courts use several methods to determine an individual’s guilt, including witness testimony, expert testimony and cross-examination. None of these methods are 100% accurate at determining a suspect’s guilt. But when they are all employed together, the jury (hopefully), is able to build a picture of the likelihood of whether or not the individual is guilty or innocent.
Nobody is suggesting that the polygraph test should be the basis on which a person’s guilt or innocence is determined. However, when used with other methods, it can play a valuable role in building a picture of guilt or innocence. For this reason, lie detector tests should be admissible in court.