hello, please summarize the following text: DNA Evidence When DNA technology burst onto the legal landscape in the late 1980s – a technology that, unlike most forensic disciplines that came before it, derived from basic scientific disciplines – the broader scientific community took notice. Initially, this impressive technology was received with great enthusiasm. But questions about its courtroom use soon emerged. In People v. Castro (15), through the involvement of talented defense counsel and distinguished scientists as defense experts, substantial concerns about how laboratory DNA science was being “translated” for courtroom use gained prominence (16). In the wake of Castro and several cases that followed, the National Research Council of the National Academy of Sciences convened a blue-ribbon committee to examine DNA evidence, and a flurry of additional scientific activity ensued. Geneticists, statisticians, evolutionary biologists, psychologists, and others debated, tested, and wrote about various aspects of this new technique in prestigious scientific journals. It was not forensic science business as usual; this time there would be no deference to authority or to the say-so of a narrowly-defined forensic community. The National Research Council ended up writing two reports, four years apart, about DNA evidence (17 [NRC I], 18 [NRC II]). We do not focus on the reports as a whole, but limit our attention to their respective treatments of testing in the forensic sciences. Two types of proficiency tests were needed to legitimate the use of DNA profiling in court. One type of test would address issues that were internal to the forensic sciences. These tests address matters such as whether examiners can follow the protocols for a particular technique, and whether different examiners and different laboratories obtain identical (or nearly identical) results on identical samples. A second type of test focused more on matters external to the day to-day workings of forensic science analyses, such as helping triers-of-fact assign appropriate weight to DNA evidence. This goal is best accomplished through another type of proficiency test designed specifically to identify accuracy and error rates under various casework-like conditions (19). As NRC I noted, “Interpretation of DNA typing results depends not only on population genetics, but also on laboratory error” (17, p. 88). This report referenced the result of a DNA proficiency test conducted a few years earlier that identified a false positive error rate of 2%. Noting that some of the early proficiency tests were “less than ideal,” NRC I stressed that, for DNA typing, “laboratory error rates must be continually estimated in blind proficiency testing and must be disclosed to juries” (17, p. 89). This testing recommendation was largely ignored by the forensic science community and the courts. Moreover, some influential forensic science voices actively counseled against error rate testing on the specious grounds that error rates are irrelevant to individual cases because they change over time (testimony from a leading FBI scientist in United States v. Llera-Plaza (20, p. 510). At trial, prosecutors argued that the source opinions of DNA examiners were reliable. With few exceptions, trial judges gave little weight to defense arguments that DNA evidence should be limited or excluded when error rate tests had not been performed. NRC II offered a different perspective on tests designed to measure laboratory error rates than that taken by NRC I. NRC II offered four arguments against performing such tests: (1) error rates are unknowable because they are always in flux, (2) error rates never translate directly into an estimate of error for a given case because each “particular case depends on many variables,” (3) general error rate estimates “penalize the better laboratories,” and (4) an “unrealistically large number of proficiency trials” would be required to obtain reliable error rate estimates (18, p. 85- 86). Although these arguments were widely rebutted (21-23), this report stifled calls for empirical testing, and made it difficult for defense attorneys to argue that the reliability of any proffered forensic science method is unknowable without such data. Fourteen years later, yet another National Research Council report was issued (24 [NAS]). This report examined a variety of non-DNA forensic science disciplines (latent prints, shoeprints, toolmarks, hair, etc.) and concluded that nearly all had failed to test their fundamental premises and claims. According to NAS, testing requires an “assessment of the accuracy of the conclusions from forensic analyses and the estimation of relevant error rates” (24, p. 122). A follow-up report by the President’s Council of Advisors on Science and Technology argued even more forcefully for empirical error rate testing programs: “Without appropriate estimates of accuracy, an examiner’s statement that two samples are similar—or even indistinguishable—is scientifically meaningless: it has no probative value, and considerable potential for prejudicial impact” (12 [PCAST], p. 6). We thus see a variety of particularized approaches to proficiency testing in the forensic sciences across blue-ribbon analyses of the topics. Three of the four reports noted above emphasized the importance of proficiency testing and the development of empirically-grounded error rates. Although there are challenges to developing meaningful error rates, the program of proficiency testing called for in the PCAST and various NAS reports is an indispensable part of the evolving scientific framework in the forensic sciences. Error rate proficiency tests have now been conducted with forensic examiners in various subfields including latent prints (25, 26), firearms and toolmarks (27, 28), and footwear (29). These studies are important steps forward and have prompted interest in how error rates should be computed and reported. A consensus has not yet emerged. Far from signaling a discipline in disarray, ongoing research and sophisticated debates depict a field that is undergoing a scientific transformation.