“Report to the President Forensic Science in Criminal Courts: Ensuring Scientific Validity of Feature-Comparison Methods”

crime-sceneForensic science has been used in courtrooms across the country. Our criminal justice system uses forensic science to punish, convict, deprive freedom and destroy lives. Many times proponents of various areas of forensic science are not scientists; they are lawyers and judges with a limited understanding of methods of validity and reliability. But what if the forensic science that’s been used is really “junk science”? Oops. Turns out a lot of “science” that’s been used to convict people is “junk science.” Also, what if there are still courtrooms allowing this “junk science’” to be used in trials? Um, oops?

Examples of these sciences include, DNA mixture analysis, bitemark analysis, latent fingerprints, shoeprints, handwriting, firearm marks, footwear, and hair. Scientific validity within the legal system is necessary, but not yet attained in many areas.

Expert witnesses have been overstating the probative value of their findings, and of the reliability of methods used over and above what the relevant science can justify. The Supreme Court has ruled that judges must determine whether the reasoning or methodology supporting the testimony of such experts is scientifically valid. But there have been serious failings where science meets the law in criminal prosecutions.

The PCAST Forensic Science Report, available online, recently released in September 2016, details all of these failures, problems, and proposes solutions for the future of such scientific methods and expert testimony. The report also gives statistics and data for exonerations and wrongful convictions. Despite this data, and many problems pointed out in the report, government officials, like the FBI have responded stating they disagree with the report’s conclusions.

Whether government entities agree with the report, to deny that it highlights significant problems in many, if not all, of the forensic methods used in the criminal justice system, is alarming. For example, the report cites to objective and reliable methodologies used, say in DNA analysis of single source and simple mixture samples. But it also refers to Lynn Garcia, General Counsel for the Texas Forensic Science Commission (TFSC) in discussions of the recent problems discovered in Texas in the subjective analysis of complex DNA mixtures. The report discusses the background leading to this discovery, initiated by an internal audit by the FBI, which reported that it had identified and corrected minor discrepancies in its population databases used to calculate statistics in DNA cases. The FBI assured labs across the state, including Texas Department of Public Safety labs, that these errors were not significant. However, when some prosecutors requested recalculation based on this notice, a larger problem in said subjective interpretations were discovered which lead to a complete review of cases involving Combined Probability of Inclusion in DNA mixture evidence, including, potentially simple mixture samples.

The fact that government entities are responding that this report is unreliable and attacks even reliable methods in forensic science is short-sighted and hypocritical. These same government entities concede that the forensic sciences are ever-evolving and change based on new knowledge, and better more reliable methods and advancements. With all the data involving labs across the state, wrongful conviction data from across the country and the knowledge that many forensic sciences involve subjective interpretations by “scientists” or expert witnesses, how can a government entity so readily dismiss this report? Even though the TFSC recognized that some of the significant changes in interpretation results were independent of the FBI’s minor errors in its population database, to state with confidence that the forensic science expert testimony used to prosecute people is reliable in the areas outlined in the report, without further validation, is irresponsible.