A new draft report from the President’s Council of Advisors on Science and Technology (PCAST) has caused concerns about the use of modern forensic science techniques in the criminal justice system, stating: “It has become increasingly clear in recent years that lack of rigor in the assessment of the scientific validity of forensic evidence is not just a hypothetical problem but a real and significant weakness in the judicial system.”

The report acknowledged PCAST’s concerns with the lack of agreement in the scientific community in analyzing complex DNA mixtures, noting: “Subjective analysis of complex DNA mixtures, including with the widely-used Combined-Probability-of-Inclusion methods, is not foundationally valid…and objective analysis of complex DNA mixtures with probabilistic genotyping software is promising, but has not yet been sufficiently and appropriately validated and their limitations to be considered reliable for all complex mixtures.”

The PCAST report also addressed the need for empirical standards in pattern-based forensic science methods, such as bite mark analysis, fingerprint matching, firearm/ballistic matching and shoe tread analysis: “In the case of bite-mark evidence, the report is especially critical. ‘PCAST finds that bitemark analysis does not meet the scientific standards for foundational validity, and is far from meeting such standards,’ it reads. ‘To the contrary, available scientific evidence strongly suggests that examiners cannot consistently agree on whether an injury is a human bitemark and cannot identify the source of [a] bitemark with reasonable accuracy.’

Related: Los Angeles Times, NDAA Letter opposing PCAST Forensic Science Report