Polygraph testing, also known as lie detector testing, has been used for many years in criminal investigations to help quickly eliminate suspects and focus resources on other leads. The technology measures physiological responses such as heart rate, blood pressure, and respiratory rate to assess whether a person is telling the truth or lying. Although it is widely used in the United States, it has been a controversial subject in other countries.

In Ireland, many people believe that polygraph evidence cannot be used in court, but this is not true. While the Garda (the national police service of the Republic of Ireland) does not use polygraph evidence in court, a defendant can present it as evidence in their defense. Ultimately, it is up to the judge to decide whether to admit the evidence and how much weight to give it.

While some critics have claimed that the polygraph is not accurate enough to be used in court, research has shown that it compares favorably to other types of evidence routinely used in court. For example, a study conducted in 1978 by Widaki and Horvath found that polygraph evidence was more accurate than handwriting evidence and significantly more accurate than fingerprint and eyewitness evidence.

When presenting polygraph evidence in court, it is essential to understand that it may not be the only evidence presented. Polygraph evidence is more compelling when it supports other evidence in a case. Additionally, polygraph evidence can be useful in cases where there is no collaborative evidence, and it is just one person’s word against another’s.

In conclusion, polygraph testing can be a valuable tool in criminal investigations and can be presented as evidence in court. Although it is not the only evidence presented in a case, it can support other evidence and help to exonerate innocent individuals.