People in California facing criminal charges may have to contend with pseudoscience in the courtroom. Some of the tests used in criminal cases and other serious legal issues, like child custody hearings, may be unreliable, outdated or inaccurate according to a study of courtroom psychological and IQ tests. These test results can still influence the types of sentences people receive or whether they are held under pre-trial detention, despite a lack of scientific rigor to back up their usage.

According to researchers, one-third of the hundreds of different psychological tests used in courtrooms have not been subjected to peer review by experts in psychology. Those that were reviewed were not necessarily well-regarded; only 40% were judged favorably as a tool for psychological evaluation while 25% were considered unreliable in the field. An Arizona State University professor said that “junk science” was being used in criminal cases with little challenge: Only 3% of cases involved contested testing due to scientific unreliability.

This is not the first study to consider the effects of shoddy scientific testing tools on defendants and others in the courtroom. Various types of forensic evidence introduced over the years and leading to many convictions and long sentences have been debunked, including some types of blood spatter evidence and arson evidence. The National Research Council said that faulty forensic evidence may have played a role in a significant number of wrongful convictions. According to the Federal Rules of Evidence, courts are only supposed to allow scientifically well-regarded testing and evidence.

A criminal conviction can lead to jail time, heavy fines and a felony criminal record that affects future employment, education and housing. A criminal defense attorney may help people charged with a crime to challenge faulty evidence or police misconduct and work to prevent a conviction.