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cold hits: innumerate DNA
From: David Farber <dave () farber net>
Date: Thu, 15 May 2008 03:45:24 -0700
________________________________________ From: Rod Van Meter [rdv () sfc wide ad jp] Sent: Wednesday, May 14, 2008 9:14 PM To: David Farber Subject: cold hits: innumerate DNA Dave, for IP, if you wish...
From the L.A. Times, via
http://www.kansascity.com/news/nation/story/614736.html California Supreme Court weighs concerns of DNA matches By JASON FELCH and MAURA DOLAN <snip> For more than three decades, Sylvester’s slaying went unsolved. Then, in 2004, a search of California’s DNA database of criminal offenders yielded an apparent breakthrough: Badly deteriorated DNA from the assailant’s sperm was linked to John Puckett, an obese, wheelchair-bound 70-year-old with a history of rape. The DNA “match” was based on fewer than half of the genetic markers typically used to connect someone to a crime, and there was no other physical evidence. Puckett insisted he was innocent, saying that although DNA at the crime scene happened to match his, it belonged to someone else. At Puckett’s trial earlier this year, the prosecutor told the jury that the chance of such a coincidence was 1 in 1.1 million. Jurors were not told, however, the statistic that leading scientists consider the most significant: the probability that the database search had hit upon an innocent person. In Puckett’s case, it was 1 in 3. The case is emblematic of a national problem, the Los Angeles Times has found. Prosecutors and crime labs across the country routinely use numbers that exaggerate the significance of DNA matches in “cold hit” cases, in which a suspect is identified through a database search. </snip> ...and a related news article at http://www.latimes.com/news/local/la-me-webdna9-2008may09,0,6637462.story (same authors) <snip> In considering the issue over the last 12 years, the two leading scientific bodies in the field -- the National Research Council and the FBI's DNA Advisory Board -- have reached the same conclusion: In cold hit cases, jurors should be given an adjusted calculation, called the database statistic, that adjusts for the number of comparisons made within a database. </snip> --Rod ------------------------------------------- Archives: http://www.listbox.com/member/archive/247/=now RSS Feed: http://www.listbox.com/member/archive/rss/247/ Powered by Listbox: http://www.listbox.com
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- cold hits: innumerate DNA David Farber (May 15)