are thus challenged to balance requests for analyses of “older” and “cold” cases with new cases and must make choices to allocate resources by prioritizing the evidence to be analyzed. In California, voters passed Proposition 69, requiring that a DNA sample be obtained from all convicted felons. This increased the workload and resulted in 235,000 backlogged cases by the end of 2005.9

These backlogs can result in prolonged incarceration for innocent persons wrongly charged and awaiting trial and delayed investigation of those who are not yet charged, and they can contribute to the release of guilty suspects who go on to commit further crimes.

The Ascendancy of DNA Analysis and a New Standard

In the 1980s, the opportunity to use the techniques of DNA technologies to identify individuals for forensic and other purposes became apparent. Early concerns about the use of DNA for forensic casework included the following: (1) whether the detection methods were scientifically valid—that is, whether they correctly identified true matches and true nonmatches and (2) whether DNA analysis of forensic samples is reliable—that is, whether it yields reproducible results under defined conditions of use. A 1990 report by the congressional Office of Technology Assessment concluded that DNA tests were both reliable and valid in the forensic context but required a strict set of standards and quality control measures before they could be widely adopted.10

In 1990, the Federal Bureau of Investigation (FBI) established guidelines for DNA analysis and proficiency testing and four years later created the Combined DNA Index System (CODIS), which allows federal, state, and local crime laboratories to exchange and compare DNA profiles electronically, thereby linking crimes to each other and to convicted offenders.

In 1992, the National Research Council (NRC) issued DNA Technology in Forensic Science, which concluded that, “No laboratory should let its results with a new DNA typing method be used in court, unless it has undergone … proficiency testing via blind trials.”11 In addition, the report cautioned that numerous questions must be answered about using DNA evidence in a forensic context that rarely had to be considered by scientists engaged in DNA research—for example, questions involving contamination, degradation, and a number of statistical issues. While confirming that


Durose, op. cit.


U.S. Congress, Office of Technology Assessment. 1990. Genetic Witness: Forensic Uses of DNA Tests. OTA-BA-438. Washington, DC: U.S. Government Printing Office, NTIS order #PB90-259110.


National Research Council. 1992. DNA Technology in Forensic Science. Washington, DC: National Academy Press, p. 55.

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