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Position of the DAB regarding DNA database “cold hits”

Position of the DAB regarding DNA database “cold hits”. Michael L. Raymer Department of Computer Science and Engineering, Biomedical Sciences Program. DNA Advisory Board (DAB). Authorized by the DNA Identification Act of 1994.

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Position of the DAB regarding DNA database “cold hits”

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  1. Position of the DAB regarding DNA database “cold hits” Michael L. Raymer Department of Computer Science and Engineering, Biomedical Sciences Program

  2. DNA Advisory Board (DAB) • Authorized by the DNA Identification Act of 1994 “…To recommend standards to the Director of the FBI which specify criteria for quality assurance and proficiency tests to be applied to the various types of DNA analysis used by forensic laboratories, including statistical and population genetics issues affecting the evaluation of the frequency of occurrence of DNA profiles calculated from pertinent population database(s);” M. L. Raymer 2006

  3. DAB membership (1) • Chairman • Chair of TWGDAM • Representative of NIST • One molecular geneticist (not affiliated with a forensic laboratory) • Two population geneticists (not affiliated with a forensic laboratory) • Three scientists from state forensic laboratories • Two scientists from local (i.e., city or county) forensic laboratories continued… M. L. Raymer 2006

  4. DAB Membership (2) • One scientist from a private forensic laboratory • One judge • An executive secretary • A quality control/quality assurance specialist • A medical or legal ethicist • A designated federal employee M. L. Raymer 2006

  5. Past DAB Members (1) • Dr. Arthur Eisenberg - Chairman • Honorable Shirley Abrahamson - Justice/Judge • Dr. Dwight Adams - Designated Federal Employee • Dr. Frederick Bieber - Molecular Geneticist • Dr. Bruce Budowle - Chairman of SWGDAM • Dr. Ranajit Chakraborty - Population Geneticist • Mr. David Coffman - State Crime Laboratory Scientist • Dr. Bernard Devlin - Population Geneticist • Dr. Marcia Eisenberg - Private Laboratory Scientist • Dr. Paul Ferrara - State Crime Laboratory Scientist M. L. Raymer 2006

  6. Past DAB Members (2) • Ms. Mary M. Gibbons - Local Crime Laboratory Scientist • Ms. M. Dawn Herkenham - Executive Secretary • Dr. Eric Juengst - Bioethicist • Ms. Susan Narveson - State Crime Laboratory • Mr. Larry Presley - Quality Control/Quality Assurance • Dr. Dennis Reeder - NIST Scientist • Dr. Mohammad Tahir - Local Crime Laboratory Scientist M. L. Raymer 2006

  7. Past DAB Members (3) • Dr. Joshua Lederberg - Chairman • Dr. Jack Ballantyne - Local Crime Laboratory Scientist • Mr. John Hicks - State Crime Laboratory • Ms. Margaret Kuo - Local Crime Laboratory Scientist • Mr. Terry Laber - State Crime Laboratory Scientist • Dr Phillip Reilly - Bioethicist • Mr. Jay Miller - Executive Secretary • Mr. Milton Ahlerich - Designated Federal Employee • Dr. Randall Murch - Designated Federal Employee M. L. Raymer 2006

  8. Sources • “Statistical and Population Genetics Issue Affecting the Evaluation of the Frequency of Occurrence of DNA Profiles Calculated From Pertinent Population Database(s)”, Forensic Science Communications, 2:3, July 2000. [FSC]http://www.fbi.gov/hq/lab/fsc/backissu/july2000/index.htm • September, 2004 statement of Dr. Bruce Budowle [Budowle] • Testimony of Dr. Ranajit Chakraborty in USA v. Anthony Jenkins, March 2005. [Chakraborty] M. L. Raymer 2006

  9. Questions regarding database hits The DAB emphasizes that different approaches provide answers to different questions, including: “What is the rarity of a specific DNA profile?” and “What is the probability of finding such a DNA profile in a specific database searched?” M. L. Raymer 2006

  10. Database hits • DAB supports the NRCII method, using the “Database Match Probability” (DMP) for answering the second question. “What is the probability of finding such a DNA profile in a specific database searched?” M. L. Raymer 2006

  11. Rarity • The DAB believes that the rarity of the genotype is also an important legal question, and that the random match probability (RMP) is the appropriate statistic for expressing this value. “What is the rarity of a specific DNA profile?” M. L. Raymer 2006

  12. Response to Balding and Donnelly • Consider the LR in a Bayesian context in which the prior probability is a function of the size of the database (Stockmarr, 1999; NRCII). • “Unfortunately, Bayesian logic has not been considered by the U.S. criminal legal system for NDA analysis. …without the Bayesian framework, the Balding and Donnelly (1996) formulation is easily misinterpreted in a fashion unfavorable to the suspect. … Thus, we continue to endorse the recommendation of the NRC II Report…” [FSC] M. L. Raymer 2006

  13. Why not provide only the DMP? • Consider an RMP of 1/1,000,000 and a database size of 1,000,000 • “If the DMP calculation were only provided to the trier of fact to convey the meaning of the rarity of the profile, it could be misinterpreted as meaning that everyone in the population shares this profile or that the profile is extremely more common than it actually is in a particular population” [Budowle] M. L. Raymer 2006

  14. What controversy? • “The mere fact that different questions and more than one statistical caclulation might be of importance to the trier of fact is not indicative of a controversy. To the contrary, it merely reveals that a single piece of forensic evidence may raise more than one question that is relevant to the trier of fact.” • A legal question, not a scientific controversy. M. L. Raymer 2006

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