The Role of Race in DNA Statistics: What Experts Say, What California Courts Allow

25 Pages Posted: 12 Feb 2007 Last revised: 14 Jun 2008

See all articles by David H. Kaye

David H. Kaye

Pennsylvania State University, Penn State Law; Arizona State University - Sandra Day O'Connor College of Law - School of Life Science

Abstract

When a defendant's DNA matches a sample found at a crime scene, how compelling is the match? To answer this question, DNA analysts typically use numbers - "relative frequencies," "random match probabilities" or "likelihood ratios." They compute and present these quantities for the major racial or ethnic groups in the United States, supplying prosecutors with such mind-boggling figures as "one in nine hundred and fifty sextillion African Americans, one in one hundred and thirty septillion Caucasians, and one in nine hundred and thirty sextillion Hispanics."

A line of California cases rejects this established practice on relevance grounds. The theory of these cases is that only the perpetrator's race is relevant to the crime; hence, it is impermissible to introduce statistics about other races. This article critiques this reasoning. Relying on the statistical concept of likelihood, it presents a logical justification for referring to a range of races and identifies some problems with the one-race-only rule. Nevertheless, even if the traditional practice is consistent with the doctrine of relevance, other ways to express the probative value of a DNA match exist. The paper therefore notes some ways to express the probative value of a DNA match quantitatively without referring to variations in DNA profile frequencies among races.

Keywords: DNA evidence, race, conditional relevance, likelihood ratio

Suggested Citation

Kaye, David H., The Role of Race in DNA Statistics: What Experts Say, What California Courts Allow. Southwestern University Law Review, Vol. 37, No. 2, pp. 304-322, 2008. Available at SSRN: https://ssrn.com/abstract=962140

David H. Kaye (Contact Author)

Pennsylvania State University, Penn State Law ( email )

University Park, PA 16802
United States

HOME PAGE: http://www.personal.psu.edu/dhk3/index.htm

Arizona State University - Sandra Day O'Connor College of Law - School of Life Science ( email )

111 E Taylor St.
Phoenix, AZ 85004
United States

HOME PAGE: http://www.personal.psu.edu/dhk3/index.htm

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