AAAS CEO Rush Holt calls for changes in new uniform language that the Justice Department has approved governing what examiners can state about latent fingerprint analysis. | Daekow/Wikimedia Commons (CC BY-SA 4.0)
The American Association for the Advancement of Science is asking the Justice Department to revise newly announced uniform language on what fingerprint examiners can use in court testimony and written reports, saying statements that “rest on speculation, rather than scientific evidence” should not be allowed.
In a March 26 letter to Justice Department Deputy Attorney General Rod Rosenstein, AAAS CEO Rush Holt said some of the new measures constitute much-needed and welcome changes relating to the testimony or statements examiners are permitted to offer in latent finger print analyses.
Still, he said, the guidelines continue to give examiners wide latitude to testify on whether distinctive ridge patterns – the loops, arches and whorls of each of a human’s 10 fingerprints – support a strong statement that they came from the same person.
“There is no scientific basis for estimating the number of individuals who might have a particular pattern of features; therefore, there is no scientific basis on which an examiner might form an expectation of whether an arrangement comes from the same source,” said Holt. “The proposed language fails to acknowledge the uncertainty that exists regarding the rarity of particular fingerprint patterns. Any expectations that an examiner asserts necessarily rest on speculation, rather than scientific evidence.”
The letter comes in response to an announcement Rosenstein made at the annual meeting of the American Academy of Forensic Sciences on Feb. 21 in Seattle disclosing that the Justice Department has approved “Uniform Language for Testimony and Reports” to be used by its forensic examiners in statements about analyses of forensic latent fingerprint evidence conducted in its labs.
While the Uniform Language forbids an examiner from making “the unsupportable claim that the pattern of features in two prints come from the same source to the exclusion of all others,” Holt said in his letter to the Justice Department, “it does allow examiners to say they ‘would not expect to see that same arrangement of features repeated in an impression that came from a different source.’”
In the letter, Holt agreed with the Justice Department’s decision to bar examiners from stating that a pair of fingerprints “originated from the same source to the absolute exclusion of all” others or expressing a level of certainty that is “absolute or numerically calculated” in an analysis comparing samples collected from crime scenes with those known by authorities to belong to identified sources.
The department’s guidance follows the release by AAAS of its forensic fingerprint analysis report last September – the “Forensic Science Assessments: A Quality and Gap Analysis of Latent Fingerprint Analysis.” That report made clear that latent fingerprint examiners may be able to rule out most of the population from being the source of a latent fingerprint, based on observed features. However, there are not enough data to allow examiners to narrow the pool of sources to a single person.
Drawing from AAAS’ fingerprint report, which includes an extensive review of the scientific literature, evaluations of when such analysis is or is not well grounded in science and a review of practices lacking scientific foundation, Holt urged the Justice Department to not permit examiners to estimate the frequency of any fingerprint observation or use the term “identification” or “source identification” in testimony or reports.
The Justice Department’s guidelines, Holt proposed, should instead instruct examiners to adopt more tempered language, which is backed by scientific evidence and steers clear of unsupportable claims.
Such language would allow examiners to note when two fingerprints display “a great deal of detail with no differences,” Holt proposed. Yet, such an observation would have to be accompanied with the admission that, “There is no way to determine how many other people might have a finger with a corresponding set of ridge features, but it is my opinion that this set of features would be unusual.”
In making the Justice Department announcement, Rosenstein also said the department would reinstitute next month the Council of Federal Forensic Laboratory Directors, a group of the heads of the government’s leading forensic laboratories and digital analysis centers; put in place a system for monitoring examiner’s courtroom testimony and regularly review the new standards “to confirm that they reflect current scientific knowledge and best practices.”
The news came a year after Attorney General Jeff Sessions disbanded the National Commission on Forensic Science, an Obama administration-era collaboration between the Justice Department and the National Institutes of Standards and Technology that brought together scientists, judicial players including prosecutors, defense lawyers, federal crime labs directors in an effort to improve forensic science.
[Associated image: Ryan J. Reilly/Flickr (CC BY 2.0)]