Forensic Science, Statistics & the Law
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Commentary on news and publications at the intersections of scientific evidence, forensic science, and statistics. Intended for people who want accurate information about forensic science and statistical reasoning in the courtroom, this blog mainly features interesting and informed comments on news articles, court opinions, books, and the like that catch the author's eye.
Forensic Science, Statistics & the Law
3M ago
Columbia University has announced that "AI Discovers That Not Every Fingerprint Is Unique"! The subtitle of the press release of January 10, 2024, boldly claims that
Columbia engineers have built a new AI that shatters a long-held belief in forensics–that fingerprints from different fingers of the same person are unique. It turns out they are similar, only we’ve been comparing fingerprints the wrong way!
Forensic Magazine immediately and uncritically rebroadcast (quoting verbatim without acknowledgment from the press release) the confused statements about uniqueness. According to the Columbi ..read more
Forensic Science, Statistics & the Law
5M ago
The Supreme Court's celebrated (but ambiguous) opinion in Daubert v. Merell Dow Pharmaceuticals, \1/ was a direct response to a seemingly simple rule--results that are not published in the peer-reviewed scientific literature are inadmissible to prove that a scientific theory or method is generally accepted in the scientific community. The Court unanimously rejected this strict rule--and more broadly, the very requirement of general acceptance--in favor of a multifaceted examination guided by four or five criteria that have come to be known as "the Daubert factors."
But "peer review and publica ..read more
Forensic Science, Statistics & the Law
5M ago
The Organization of Scientific Area Committees for Forensic Science (OSAC) has an online "lexicon" that collects definitions of terms as they appear in published standards. 1/ These may or may not be the same as definitions in textbooks or other authoritative sources. 2/ They may or may not be accurate. (Yet, the drafters of OSAC standards sometimes point to the existence of a definition in the compendium as if it were a conclusive reason to perpetuate it. 3/)
Speaking of "accurate," the word "accuracy" has five overlapping definitions in OSAC's lexicon:
Closeness of agreement between a measu ..read more
Forensic Science, Statistics & the Law
5M ago
SWGDE 22-F-003-1.0, Best Practices for Remote Collection of Digital Evidence from a Networked Computing Environment, is a forensic-science standard proposed for inclusion on the Organization of Scientific Area Committees for Forensic Science (OSAC) Registry—"a repository of selected published and proposed standards … to promote valid, reliable, and reproducible forensic results.”
The best practices “may not be applicable in all circumstances.” In fact, “[w]hen warranted, an examiner may deviate from these best practices and still obtain reliable, defensible results.” I guess that is why they a ..read more
Forensic Science, Statistics & the Law
5M ago
The National Institute of Justice (NIJ) "is the research, development and evaluation agency of the U.S. Department of Justice . . . dedicated to improving knowledge and understanding of crime and justice issues through science." It offers a series of webpages and video recordings (a "training course") on Population Genetics and Statistics for Forensic Analysts. The course should be approached with caution. I have not worked through all the pages and videos, but here are a few things that rang alarm bells:
NIJ's Training
Comment
Many statisticians have employed what is known as Bayes ..read more
Forensic Science, Statistics & the Law
5M ago
The likelihood ratio (LR) is essentially a number that expresses how many times more probable the data from an experiment are if one hypothesis is true than if another hypothesis is true. For example, suppose we make a single measurement of the height of a known individual. Then we do the same for an individual who is covered from head to foot by a sheet. We want know if we have measured the same individual twice or two different individuals once. The closer the two measured heights are to one another, the more the measurements support the same-source hypothesis as opposed to the different-sou ..read more
Forensic Science, Statistics & the Law
5M ago
Last month, in United States v. Ware, 69 F.4th 830 (11th Cir. 2023), the U.S. Court of Appeals for the Eleventh Circuit "carefully review[ed]" the convictions of Dravion Sanchez Ware arising out of a month-long crime spree near Atlanta, in 2017. He was found to have participated "in robbing ... three spas, four massage parlors, a nail salon, and a restaurant." The opinion recounts the nine brutal robberies in luxuriant detail. It also discusses Mr. Ware's argument that the district court erred "by not holding a formal Daubert hearing before admitting expert fingerprint evidence."
I ..read more
Forensic Science, Statistics & the Law
5M ago
This week, the Maryland Supreme Court became the first state supreme court to hold, unequivocally, that a firearms-toolmark examiner may not testify that a bullet was fired from a particular gun without a disclaimer indicating that source attribution is not a scientific or practical certainty. \1/ The opinion followed two trials, \2/ two evidentiary hearings (one on general scientific acceptance \3/ and one on the scientific validity of firearms-toolmark identifications \4/) and affidavits from experts in research methods or statistics. The Maryland court did not discuss the content of the req ..read more
Forensic Science, Statistics & the Law
5M ago
In October 2022, NIST released a draft report entitled "Bitemark Analysis: A NIST Scientific Foundation Review." A press release announced "Forensic Bitemark Analysis Not Supported by Sufficient Data, NIST Draft Review Finds." In March 2023, the final version reaching the same conclusions was released. Soon afterward, the NIST-supported Organization of Scientific Area Committees for Forensic Science (OSAC) revised the scope of the work that its forensic odontology subcommittee can undertake. The description now specifies, in italics no less, that "The Forensic Odontology Subcommittee does not ..read more
Forensic Science, Statistics & the Law
5M ago
Yesterday I heard about some new publications on forensic hair microscopy published in, of all places, a journal on pharmaceuticals. My first thought was that the journal might be a predatory one with deceptive advertising designed to con scholars into paying for publication in what appears to be a reputable scientific journal. But that was too cynical.
The papers are
S. Sneha Harshini, Vishnu Priya Veeraraghavan, Abirami Arthanari1, R. Gayathri, S. Kavitha, J. Selvaraj, P. K. Reshma & Y. Dinesh, Comparative Study of Male and Female Human Hair: A Microscopic Analysis, 13 J. Advanced Pharm ..read more