How can Francis Bacon help forensic science? The four idols of human biases

Much debate has focused on whether forensic science is indeed a science. This paper is not aimed at answering, or even trying to contribute to, this question. Rather, in this paper I try to find ways to improve forensic science by identifying potential vulnerabilities. To this end I use Francis Bacon's doctrine of idols which distinguishes between different types of human biases that may prevent scientific and objective inquiry. Bacon’s doctrine contains four sources for such biases: Idols Tribus (of the 'tribe'), Idols Specus (of the 'den'/'cave'), Idols Fori (of the 'market'), and Idols Theatre (of the 'theatre'). While his 400 year old doctrine does not, of course, perfectly match up with our current world view, it still provides a productive framework for examining and cataloguing some of the potential weaknesses and limitations in our current approach to forensic science

The Proficiency of Experts

Expert evidence plays a crucial role in civil and criminal litigation. Changes in the rules concerning expert admissibility, following the Supreme Court\u27s Daubert ruling, strengthened judicial review of the reliability and the validity of an expert\u27s methods. Judges and scholars, however, have neglected the threshold question for expert evidence: whether a person should be qualified as an expert in the first place. Judges traditionally focus on credentials or experience when qualifying experts without regard to whether those criteria are good proxies for true expertise. We argue that credentials and experience are often poor proxies for proficiency. Qualification of an expert presumes that the witness can perform in a particular domain with a proficiency that non-experts cannot achieve, yet many experts cannot provide empirical evidence that they do in fact perform at high levels of proficiency. To demonstrate the importance ofproficiency data, we collect and analyze two decades of proficiency testing of latent fingerprint examiners. In this important domain, we found surprisingly high rates of false positive identifications for the period 1995 to 2016. These data would qualify the claims of many fingerprint examiners regarding their near infallibility, but unfortunately, judges do not seek out such information. We survey the federal and state case law and show how judges typically accept expert credentials as a proxy for proficiency in lieu of direct proof of proficiency. Indeed, judges often reject parties\u27 attempts to obtain and introduce at trial empirical data on an expert\u27s actual proficiency. We argue that any expert who purports to give falsifiable opinions can be subjected to proficiency testing and that proficiency testing is the only objective means of assessing the accuracy and reliability ofexperts who rely on subjective judgments to formulate their opinions (so-called black-box experts ). Judges should use proficiency data to make expert qualification decisions when the data is available, should demand proof of proficiency before qualifying black-box experts, and should admit at trial proficiency data for any qualified expert. We seek to revitalize the standard for qualifying experts: expertise should equal proficiency

Fixing Rule 702: The PCAST Report and Steps to Ensure the Reliability of Forensic Feature-Comparison Methods in the Criminal Courts

In response to PCAST’s recommendation, the Standing Advisory Committee on Evidence Rules convened a meeting on forensic expert testimony, Daubert, and Rule 702 on October 27, 2017, at Boston College Law School to inform itself about the issues.22 The meeting included presentations by twenty-six speakers (including myself) and discussion among the attendees. The purpose of this Article is to summarize aspects of the PCAST report relevant to its recommendation to the Standing Advisory Committee on Evidence Rules and to propose a path forward with respect to Rule 702

Honesty Without Truth: Lies, Accuracy, and the Criminal Justice Process

Focusing on “lying” is a natural response to uncertainty but too narrow of a concern. Honesty and truth are not the same thing and conflating them can actually inhibit accuracy. In several settings across investigations and trials, the criminal justice system elevates compliant statements, misguided beliefs, and confident opinions while excluding more complex evidence. Error often results. Some interrogation techniques, for example, privilege cooperation over information. Those interactions can yield incomplete or false statements, confessions, and even guilty pleas. Because of the impeachment rules that purportedly prevent perjury, the most knowledgeable witnesses may be precluded from taking the stand. The current construction of the Confrontation Clause right also excludes some reliable evidence—especially from victim witnesses—because it favors face-to-face conflict even though overrated demeanor cues can mislead. And courts permit testimony from forensic experts about pattern matches, such as bite-marks and ballistics, if those witnesses find their own methodologies persuasive despite recent studies discrediting their techniques. Exploring the points of disconnect between honesty and truth exposes some flaws in the criminal justice process and some opportunities to advance fact-finding, truth-seeking, and accuracy instead. At a time when “post-truth” challenges to shared baselines beyond the courtroom grow more pressing, scaffolding legal institutions, so they can provide needed structure and helpful models, seems particularly important. Assessing the legitimacy of legal outcomes and fostering the engagement necessary to reach just conclusions despite adversarial positions could also have an impact on declining facts and decaying trust in broader public life

Invalid Forensic Science Testimony and Wrongful Convictions

This is the first study to explore the forensic science testimony by prosecution experts in the trials of innocent persons, all convicted of serious crimes, who were later exonerated by post-conviction DNA testing. Trial transcripts were sought for all 156 exonerees identified as having trial testimony by forensic analysts, of which 137 were located and reviewed. These trials most commonly included testimony concerning serological analysis and microscopic hair comparison, but some included bite mark, shoe print, soil, fiber, and fingerprint comparisons, and several included DNA testing. This study found that in the bulk of these trials of innocent defendants - 82 cases or 60% - forensic analysts called by the prosecution provided invalid testimony at trial - that is, testimony with conclusions misstating empirical data or wholly unsupported by empirical data. This was not the testimony of a mere handful of analysts: this set of trials included invalid testimony by 72 forensic analysts called by the prosecution and employed by 52 laboratories, practices, or hospitals from 25 states. Unfortunately, the adversarial process largely failed to police this invalid testimony. Defense counsel rarely cross-examined analysts concerning invalid testimony and rarely obtained experts of their own. In the few cases in which invalid forensic science was challenged, judges seldom provided relief. This evidence supports efforts to create scientific oversight mechanisms for reviewing forensic testimony and to develop clear scientific standards for written reports and testimony. The scientific community can through an official government entity promulgate standards to ensure the valid presentation of forensic science in criminal cases and thus the integrity and fairness of the criminal process

Realistic Man, Fantasy Policeman: The Longevity of Ruth Rendell's Reginald Wexford

Publisher does not allow open access until after publicatio

Invalid Forensic Science Testimony and Wrongful Convictions

This is the first study to explore the forensic science testimony by prosecution experts in the trials of innocent persons, all convicted of serious crimes, who were later exonerated by post-conviction DNA testing. Trial transcripts were sought for all 156 exonerees identified as having trial testimony by forensic analysts, of which 137 were located and reviewed. These trials most commonly included testimony concerning serological analysis and microscopic hair comparison, but some included bite mark, shoe print, soil, fiber, and fingerprint comparisons, and several included DNA testing. This study found that in the bulk of these trials of innocent defendants - 82 cases or 60% - forensic analysts called by the prosecution provided invalid testimony at trial - that is, testimony with conclusions misstating empirical data or wholly unsupported by empirical data. This was not the testimony of a mere handful of analysts: this set of trials included invalid testimony by 72 forensic analysts called by the prosecution and employed by 52 laboratories, practices, or hospitals from 25 states. Unfortunately, the adversarial process largely failed to police this invalid testimony. Defense counsel rarely cross-examined analysts concerning invalid testimony and rarely obtained experts of their own. In the few cases in which invalid forensic science was challenged, judges seldom provided relief. This evidence supports efforts to create scientific oversight mechanisms for reviewing forensic testimony and to develop clear scientific standards for written reports and testimony. The scientific community can through an official government entity promulgate standards to ensure the valid presentation of forensic science in criminal cases and thus the integrity and fairness of the criminal process