[Clips] Fingerprint Matches Come Under More Fire As Potentially Fallible

[R.A. Hettinga]

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 Date: Fri, 7 Oct 2005 13:24:14 -0400
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 Subject: [Clips] Fingerprint Matches Come Under More Fire As Potentially
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 <http://online.wsj.com/article_print/SB112864132376462238.html>

 The Wall Street Journal

  October 7, 2005
  SCIENCE JOURNAL
  By SHARON BEGLEY



 Fingerprint Matches
  Come Under More Fire
  As Potentially Fallible
 October 7, 2005; Page B1

 Fingerprint examiners would probably be happy if they never heard the name
 "Brandon Mayfield" again, but for researchers who study the scientific
 basis for fingerprint identification Mr. Mayfield is the gift that keeps on
 giving.

 Mr. Mayfield is the Portland, Ore., lawyer and Muslim convert whose prints
 the FBI matched to those taken from a suspicious bag near one of the 2004
 Madrid train bombings. When Spanish police insisted the prints didn't match
 Mr. Mayfield's -- and eventually linked them to an Algerian living in Spain
 -- the FBI conceded the error and apologized to the jailed Mr. Mayfield.

 Since such an error is supposed to be impossible (an FBI handbook says, "Of
 all the methods of identification, fingerprinting alone has proved to be
 both infallible and feasible"), the case has achieved a certain notoriety.
 So when scientists recently tested fingerprint IDs, they told examiners one
 set of prints were from Mr. Mayfield and the other set from the Madrid
 bombings. "We told them we were trying to understand what went wrong in
 that case," says Itiel Dror of Britain's University of Southampton, who did
 the study with student David Charlton. "Could they please look at the
 prints and tell us where the examiners had gone wrong."

 One examiner said he couldn't tell if the pair matched. Three said the pair
 did not match and helpfully pointed out why. The fifth examiner insisted
 the prints -- notorious for not matching -- did match.

 Give that one a gold star.

 Unbeknown to the examiners, the prints were not from Madrid and Mr.
 Mayfield. They were pairs that each examiner had testified in recent
 criminal cases came from the same person. The three who told the scientists
 that their pair didn't match therefore reached a conclusion opposite to the
 one they had given in court; another expressed uncertainty, whereas in
 court he had been certain. Prof. Dror will present the study later this
 month at the Biometrics 2005 meeting in London.

 A study this small would hardly show up on scientists' radar screens. But
 it comes at a time when traditional forensic sciences -- analysis of bite
 marks, bullets, hair, handwriting and fingerprints -- are facing skepticism
 over the validity of their core claim: that when two marks are not
 observably different, they were produced by the same person or thing.

 Michael Saks of Arizona State University, Tempe, argues that the claim
 lacks "theoretical and empirical foundation." There is no basic science
 that predicts how often marks that match on some number of characteristics
 actually come from different people, as there is for DNA typing. And data
 on the frequency of false matches are sparse.

 It isn't just fingerprints. Last month the FBI announced that its lab would
 no longer try to match bullets by the trace elements they contain. Although
 the FBI "still firmly supports the scientific foundation of bullet lead
 analysis," the bureau said, "neither scientists nor bullet manufacturers
 are able to definitively attest to the significance of an association made
 between bullets."

 That decision may be the first move toward what Prof. Saks calls "the
 coming paradigm shift in forensic science." For too long, he argues,
 forensic science has been excused from rigorous research on how frequently
 attributes (ridges and whorls in fingerprints, trace amounts of tin or
 antimony in bullets) vary and on the probability that marks with identical
 attributes come from different people or objects.

 In the most serious break with rigorous science, forensic science often
 regards the very notion of probability as anathema. The International
 Association for Identification, the largest forensic group, says testifying
 about "possible, probable or likely identification shall be deemed ...
 conduct unbecoming." Only 100% certainty will do. The pioneers of DNA
 typing, in contrast, calculated the probability of false matches, making
 DNA the most scientific forensic science.

 The unsupported, and unscientific, claim of infallibility is being tested
 in Massachusetts' highest court, which last month heard an appeal on the
 admissibility of fingerprints. Defense lawyers argued that the technique
 falls short of the standard the U.S. Supreme Court established in its 1993
 "junk science" decision. The decision held that scientific testimony must
 have a known error rate. It will be interesting to see how much longer
 fingerprinting can get away with "zero."

 What is it if not zero? FBI proficiency exams since 1983 find an error rate
 of 0.8%. Multiplied by the millions of cases crime labs process, that works
 out to about 1,900 possible mismatches every year. But misattributions
 "appear to be occurring at an accelerating rate," says Simon Cole of the
 University of California, Irvine, who recently compiled 22 cases of
 mismatches for a study in the Journal of Criminal Law and Criminology. That
 rise, he suggests, may reflect the fact that examiners are "under greater
 scrutiny."

 According to a 2002 handbook of forensic science, error rates are not what
 you see on TV. They're as high as 63% for voice ID, 40% for handwriting,
 64% for bite marks, 12% for hair. The real numbers may be even higher:
 Blind tests, slipped into an examiner's workload rather than marked,
 "Here's the test!", are essentially nonexistent.

 --
 -----------------
 R. A. Hettinga <mailto: rah at ibuc.com>
 The Internet Bearer Underwriting Corporation <http://www.ibuc.com/>
 44 Farquhar Street, Boston, MA 02131 USA
 "... however it may deserve respect for its usefulness and antiquity,
 [predicting the end of the world] has not been found agreeable to
 experience." -- Edward Gibbon, 'Decline and Fall of the Roman Empire'
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-- 
-----------------
R. A. Hettinga <mailto: rah at ibuc.com>
The Internet Bearer Underwriting Corporation <http://www.ibuc.com/>
44 Farquhar Street, Boston, MA 02131 USA
"... however it may deserve respect for its usefulness and antiquity,
[predicting the end of the world] has not been found agreeable to
experience." -- Edward Gibbon, 'Decline and Fall of the Roman Empire'

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