There are various forms of evidentary tests that are essentially not allowed in the jurisdiction of criminal trials. The prohibition of these tests was mainly implemented after competent analysis and consideration being given based on their respective validity and admissibility into criminal trials.
Validity of Lie Detector Tests The use of lie detectors was long ago prohibited from criminal trials due to their lack of repetitive confirmatory acceptance as being adequately valid. For instance, according to Illinois law the establishment of two statutes was found necessary in which the trial judge is essentially prohibited from putting a requirement or request regarding the submission of the accused to a lie detector in order to ascertain trth (Graham, 2004). This not only applies to the accused but to both parties participating in the court’s jurisdiction. “The Frye rule for the admissibility of scientific evidence was formulated in a criminal case in which a defendant tried to introduce a precursor of lie detector tests. That court held that novel scientific evidence or methodology on which an expert relied to testify had to have ‘general acceptance’ in the relevant scientific community to be admitted for consideration at criminal trial” (Cranor, 2006).The Admissibility of Expert Opinions based on Unfounded Research Opinions The increasing application of research results and conclusions especially based on psychological examinations of criminal trials has become of increeasing concern.
In the recent past, the use of unfounded research opinions coming from experts as a test mechanism of establishing the accused’s involvement in a case has been prohibited (Cedric, 2005). This is especially considering the lack of sufficient replicability studies carried out on the same. “If scientific, technical, or other specialized knowledge will assist the Trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case” (Cranor, 2006).