It should be noted that, at least in California, the Frye rule does not require absolute "unanimity of views within the scientific community," which, according to the California Court of Appeals, would "demand the impossible." In People v. Guerra （restated in the Reilly case）, the court ruled that, "the test is met if the use of the technique is supported by a clear majority of the members of that community." Nevertheless, some courts have interpreted "general acceptance" to mean the absence of controversy, an unrealistic standard in almost any scientific or technical area.
One result of this interpretation is that Frye hearings often last longer than many trials. The mother of all Frye hearings took place in San Diego in 1987. At issue was the methodology of pre-DNA blood typing. A personal vendetta between two experts, known as the "starch wars," exacerbated the controversy which dragged on for a full year. While courts and attorneys are often reluctant to reveal the costs of proceedings, Frye hearings are expensive.
In King County （Seattle）, Washington the situation may be the worst in the country. There have been over a dozen pre-trial DNA evidentiary hearings in this jurisdiction, each requiring two to six weeks of courtroom time. Most have concerned identical technologies and laboratories. In total, these hearings are estimated to have cost the local government over $1,000,000, not counting the time that personnel such as bailiffs and guards, attorneys, experts and others have lost to more productive tasks. This might be a reasonable price to pay if the controversy had been finally settled, but at this point there is no end in sight. All costs are paid by the state in more than 90% of these cases because the defendant is indigent.
The Frye rule has been criticized for its overly conservative approach and its vulnerability to manipulation by those seeking to exclude novel scientific evidence. After the Federal Rules of Evidence were enacted, a number of jurisdictions abandoned Frye.
The Federal Standard
The Federal Rules of Evidence currently in force were promulgated by the Supreme Court and enacted by Congress in 1975. While they are applicable directly only to proceedings in federal courts, they serve as the model for evidence codes in 32 states. Despite this state recognition of federal standards, the majority of states profess to follow the Frye rule, creating evidenciary ambiguity that may not be resolved until appellate courts or legislatures address the issue.
While not explicitly repudiating the Frye rule, the Federal Rules adopt a more permissive approach. They liken the standard for scientific evidence to that for other evidence, i.e. whether the probativeness, materiality, and reliability of the evidence outweighs its tendency to mislead, prejudice, and confuse the jury. The judge has more discretion under the Federal Rules.
Rule 702, which concerns admissibility, states：
if scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise. Rule 703 requires that the facts or data presented be "of a type reasonably relied on by experts in the particular field." Rule 403 excludes evidence that would cause undue prejudice or confusion. Proponents of the Federal Rules approach to admissibility believe that taken together, these rules address all the concerns embodied in the Frye rule.
Daubert v. Merrell Dow
Critics of the Federal Rules fear that the courts may be opening themselves to "junk science" by relaxing Frye, but a landmark case heard by the Supreme Court in 1993 rejected that claim. In Daubert v. Merrell Dow Pharmaceutical, Inc., the court unanimously held that the Frye rule was incompatible with and had been superseded by the adoption of the Federal Rules. It found that "vigorous cross-examination, presentation of contrary evidence, and careful [jury] instruction are the traditional and appropriate means of attacking shaky but admissible evidence." Trial courts also could still render summary judgments and directed verdicts where there was an insufficient showing of reliability.
The effect of Daubert on states where rules mirror federal standards has yet to be felt. However, it is reasonable to assume that expert testimony on DNA will be admissible after a threshold finding that it is relevant and reliable. Defendants in these jurisdictions will have a harder time suppressing DNA evidence, although stiff challenges to its admissibility will undoubtedly continue, at least for the near future. Daubert will have little or no effect on states where Frye still prevails. Some of the states even have supreme court decisions affirming Frye. The most recent state to affirm Frye is California in the Leahy case, decided in October 1994. In these states, new high court decisions or legislation are the only means to change admissibility standards.
Legislated Admissibility
By the Fall of 1994, eleven states had statutes mandating the admissibility of DNA evidence. Maryland became the first state to do so followed by Minnesota, Louisiana, and Nevada, all in 1989. Most of the legislation contains language that DNA testing is acceptable "without antecedent expert testimony" that it is "a trustworthy and reliable method." Arguably, these laws do not cover DNA analysis methods introduced after their passage, and the defense may still challenge laboratory performance and the statistical interpretation of results. As a more sophisticated defense bar mounts increasing numbers of expensive challenges to DNA evidence, it is likely that additional state legislatures will address this issue.
Expert Witnesses
While many expert witnesses represent the best in their profession, the proliferation of expert witnesses, often considered to be "hired guns" employed to shoot holes in the other side's testimony, is a remarkable development in the criminal justice system. There is hardly any kind of case not affected by these duelling experts, but psychological, medical, and DNA testimony seems to bring out the worst of them. It is difficult not to conclude that some of these individuals are willing to stretch or ignore the facts, distort the science, and become "liars for hire." Many of these witnesses derive a substantial amount or even the bulk of their income from testifying, which should be considered in determining their credibility and weighing their testimony. One California judge bemoaned the use of such witnesses by candidly calling them the beneficiaries of "a welfare system for academics." A recent article on the ethics and responsibility of expert witnesses suggests the following criteria for qualification：
Undergraduate and graduate degrees in the relevant field of expertise；Specialized training in the subject area as it relates to forensic science；Some training in forensics；Professional licenses or certifications required by professional groups in the expert's discipline；Evidence of experimentation, teaching, and publication within the specialty area； and Prior disciplinary evidence directly relevant to the issues being considered.
Other elements that help to determine an expert's qualifications include： post-graduate training, publication in peer-reviewed scientific journals, the development of accepted tests and procedures, membership or leadership in appropriate scientific societies, and, only lastly, experience as an expert witness.
Ten years ago the Califonia case People v. Brown added criteria that has proven difficult to apply, ie., that the witness "must also be 錳mpartial,' that is, not so personally invested in establishing the acceptance of a technique that he might not be objective about disagreements within the relevant scientific community." Neither should a witness be so invested in denigrating a technique that he exaggerates the disagreement within the scientific community. Probably the best way of gaining the testimony of impartial witnesses is for courts, rather than litigants, to appoint and pay for expert witnesses. Such is the practice in many other countries. While it is unusual in the U.S, this procedure is within the power of state and federal courts. A notable example in a case involving DNA was United States v. Yee, where the magistrate called Eric Lander, a mathematician-turned-geneticist, as an expert witness to supplement the seventeen expert witnesses called by the prosecution and defense. It is reported that Judge Ito may call his own expert witnesses during the Simpson case Kelly-Frye hearing.
Defense Strategy
Defense witnesses mount various objections to DNA evidence. They no longer try to discredit the technology itself. Years ago, DNA typing achieved such wide acceptance and proven reliability that opponents now concentrate on two principal points of attack： （1） the quality and methodology of the laboratory work, including the lab's error rate, and （2） the statistical interpretation of data. The focus of the attacks on admissibility have changed over time. As one objection was knocked down, DNA opponents came up with another. The quality and relevancy of the arguments and of the experts is decreasing, having gone from population geneticists to bio-statisticians to statisticians from completely unrelated fields. What follows is a summary of the most frequently heard complaints about DNA typing and the responses to them that might be expected from forensic scientists. More technical objections, such as bandshifting and laboratory quality assurance, are addressed in Chapter Three.
Conflict of Interest
Prosecution and defense expert witnesses in DNA cases are arguably the most contentious and disparaging in the business. Several judges have remarked that Frye hearings over DNA can be extremely vicious. Among the charges and countercharges hurled back and forth is that the opposing witnesses should be disqualified from testifying because of a conflict of interest. To a certain extent, both sides are correct. The prosecution believes that defense witnesses in DNA hearings often have a vested interest in making sure that the subject stays controversial so that they can continue the lucrative practice of testifying. The defense often believes that a practicing forensic scientist has a built-in bias or predisposition toward the prosecution's side because of the close working relationship between crime labs and law enforcement. Indeed, criminalists often are police employees.
If the forensic scientists are leaders in their field, they may be subject to a further conflict of interest. If they have developed or invented techniques or tools, they may have a proprietary interest in advancing DNA testing. They may have financial holdings in DNA labs or may have received grant funding from public or private agencies. Certainly, a jury is entitled to know about all of these connections which should be fully disclosed. At the same time, courts acknowledge that, "simply because learned experts earn a living with their expertise should not prohibit the admissibility of their opinions," as the court ruled in a recent New Jersey case.
Integrity of Specimen
Opposing expert witnesses try to raise doubts about the way DNA evidence was gathered and tested claiming that contamination may have occurred. The usual argument is that the underlying procedures for forensic DNA testing were developed in laboratories where pure and known samples were used and retesting always was an option. While this is true, the argument doesn't mention the usual results of contamination, the ease with which it can be detected, and the safeguards that are in place in most forensic DNA labs.
In almost all cases, the results of using a specimen sufficiently contaminated to alter test results simply would be ruled inconclusive. One way a specimen might be contaminated is by genetic material from the technician performing the analysis or from the person gathering the evidence. Again, this could not possibly harm the accused as an exclusion would be the result of such mishandling. Finally, there is the possibility that some of the DNA drawn from the suspect could be accidentally mixed with DNA retrieved from the crime scene. Such an accident would yield false results, especially if PCR amplification is used. To avoid this possibility, crime labs that perform PCR do it in isolation and under stringent conditions that minimize the risk of contamination.
DNA analysis is undeniably better than other tests in analyzing mixed specimens and overcoming a variety of contaminants. Because of its structure and relative stability, DNA can be tested even after mixture with acids, bases, gasoline, oil, or bleach.
Error Rate
One result of this interpretation is that Frye hearings often last longer than many trials. The mother of all Frye hearings took place in San Diego in 1987. At issue was the methodology of pre-DNA blood typing. A personal vendetta between two experts, known as the "starch wars," exacerbated the controversy which dragged on for a full year. While courts and attorneys are often reluctant to reveal the costs of proceedings, Frye hearings are expensive.
In King County （Seattle）, Washington the situation may be the worst in the country. There have been over a dozen pre-trial DNA evidentiary hearings in this jurisdiction, each requiring two to six weeks of courtroom time. Most have concerned identical technologies and laboratories. In total, these hearings are estimated to have cost the local government over $1,000,000, not counting the time that personnel such as bailiffs and guards, attorneys, experts and others have lost to more productive tasks. This might be a reasonable price to pay if the controversy had been finally settled, but at this point there is no end in sight. All costs are paid by the state in more than 90% of these cases because the defendant is indigent.
The Frye rule has been criticized for its overly conservative approach and its vulnerability to manipulation by those seeking to exclude novel scientific evidence. After the Federal Rules of Evidence were enacted, a number of jurisdictions abandoned Frye.
The Federal Standard
The Federal Rules of Evidence currently in force were promulgated by the Supreme Court and enacted by Congress in 1975. While they are applicable directly only to proceedings in federal courts, they serve as the model for evidence codes in 32 states. Despite this state recognition of federal standards, the majority of states profess to follow the Frye rule, creating evidenciary ambiguity that may not be resolved until appellate courts or legislatures address the issue.
While not explicitly repudiating the Frye rule, the Federal Rules adopt a more permissive approach. They liken the standard for scientific evidence to that for other evidence, i.e. whether the probativeness, materiality, and reliability of the evidence outweighs its tendency to mislead, prejudice, and confuse the jury. The judge has more discretion under the Federal Rules.
Rule 702, which concerns admissibility, states：
if scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise. Rule 703 requires that the facts or data presented be "of a type reasonably relied on by experts in the particular field." Rule 403 excludes evidence that would cause undue prejudice or confusion. Proponents of the Federal Rules approach to admissibility believe that taken together, these rules address all the concerns embodied in the Frye rule.
Daubert v. Merrell Dow
Critics of the Federal Rules fear that the courts may be opening themselves to "junk science" by relaxing Frye, but a landmark case heard by the Supreme Court in 1993 rejected that claim. In Daubert v. Merrell Dow Pharmaceutical, Inc., the court unanimously held that the Frye rule was incompatible with and had been superseded by the adoption of the Federal Rules. It found that "vigorous cross-examination, presentation of contrary evidence, and careful [jury] instruction are the traditional and appropriate means of attacking shaky but admissible evidence." Trial courts also could still render summary judgments and directed verdicts where there was an insufficient showing of reliability.
The effect of Daubert on states where rules mirror federal standards has yet to be felt. However, it is reasonable to assume that expert testimony on DNA will be admissible after a threshold finding that it is relevant and reliable. Defendants in these jurisdictions will have a harder time suppressing DNA evidence, although stiff challenges to its admissibility will undoubtedly continue, at least for the near future. Daubert will have little or no effect on states where Frye still prevails. Some of the states even have supreme court decisions affirming Frye. The most recent state to affirm Frye is California in the Leahy case, decided in October 1994. In these states, new high court decisions or legislation are the only means to change admissibility standards.
Legislated Admissibility
By the Fall of 1994, eleven states had statutes mandating the admissibility of DNA evidence. Maryland became the first state to do so followed by Minnesota, Louisiana, and Nevada, all in 1989. Most of the legislation contains language that DNA testing is acceptable "without antecedent expert testimony" that it is "a trustworthy and reliable method." Arguably, these laws do not cover DNA analysis methods introduced after their passage, and the defense may still challenge laboratory performance and the statistical interpretation of results. As a more sophisticated defense bar mounts increasing numbers of expensive challenges to DNA evidence, it is likely that additional state legislatures will address this issue.
Expert Witnesses
While many expert witnesses represent the best in their profession, the proliferation of expert witnesses, often considered to be "hired guns" employed to shoot holes in the other side's testimony, is a remarkable development in the criminal justice system. There is hardly any kind of case not affected by these duelling experts, but psychological, medical, and DNA testimony seems to bring out the worst of them. It is difficult not to conclude that some of these individuals are willing to stretch or ignore the facts, distort the science, and become "liars for hire." Many of these witnesses derive a substantial amount or even the bulk of their income from testifying, which should be considered in determining their credibility and weighing their testimony. One California judge bemoaned the use of such witnesses by candidly calling them the beneficiaries of "a welfare system for academics." A recent article on the ethics and responsibility of expert witnesses suggests the following criteria for qualification：
Undergraduate and graduate degrees in the relevant field of expertise；Specialized training in the subject area as it relates to forensic science；Some training in forensics；Professional licenses or certifications required by professional groups in the expert's discipline；Evidence of experimentation, teaching, and publication within the specialty area； and Prior disciplinary evidence directly relevant to the issues being considered.
Other elements that help to determine an expert's qualifications include： post-graduate training, publication in peer-reviewed scientific journals, the development of accepted tests and procedures, membership or leadership in appropriate scientific societies, and, only lastly, experience as an expert witness.
Ten years ago the Califonia case People v. Brown added criteria that has proven difficult to apply, ie., that the witness "must also be 錳mpartial,' that is, not so personally invested in establishing the acceptance of a technique that he might not be objective about disagreements within the relevant scientific community." Neither should a witness be so invested in denigrating a technique that he exaggerates the disagreement within the scientific community. Probably the best way of gaining the testimony of impartial witnesses is for courts, rather than litigants, to appoint and pay for expert witnesses. Such is the practice in many other countries. While it is unusual in the U.S, this procedure is within the power of state and federal courts. A notable example in a case involving DNA was United States v. Yee, where the magistrate called Eric Lander, a mathematician-turned-geneticist, as an expert witness to supplement the seventeen expert witnesses called by the prosecution and defense. It is reported that Judge Ito may call his own expert witnesses during the Simpson case Kelly-Frye hearing.
Defense Strategy
Defense witnesses mount various objections to DNA evidence. They no longer try to discredit the technology itself. Years ago, DNA typing achieved such wide acceptance and proven reliability that opponents now concentrate on two principal points of attack： （1） the quality and methodology of the laboratory work, including the lab's error rate, and （2） the statistical interpretation of data. The focus of the attacks on admissibility have changed over time. As one objection was knocked down, DNA opponents came up with another. The quality and relevancy of the arguments and of the experts is decreasing, having gone from population geneticists to bio-statisticians to statisticians from completely unrelated fields. What follows is a summary of the most frequently heard complaints about DNA typing and the responses to them that might be expected from forensic scientists. More technical objections, such as bandshifting and laboratory quality assurance, are addressed in Chapter Three.
Conflict of Interest
Prosecution and defense expert witnesses in DNA cases are arguably the most contentious and disparaging in the business. Several judges have remarked that Frye hearings over DNA can be extremely vicious. Among the charges and countercharges hurled back and forth is that the opposing witnesses should be disqualified from testifying because of a conflict of interest. To a certain extent, both sides are correct. The prosecution believes that defense witnesses in DNA hearings often have a vested interest in making sure that the subject stays controversial so that they can continue the lucrative practice of testifying. The defense often believes that a practicing forensic scientist has a built-in bias or predisposition toward the prosecution's side because of the close working relationship between crime labs and law enforcement. Indeed, criminalists often are police employees.
If the forensic scientists are leaders in their field, they may be subject to a further conflict of interest. If they have developed or invented techniques or tools, they may have a proprietary interest in advancing DNA testing. They may have financial holdings in DNA labs or may have received grant funding from public or private agencies. Certainly, a jury is entitled to know about all of these connections which should be fully disclosed. At the same time, courts acknowledge that, "simply because learned experts earn a living with their expertise should not prohibit the admissibility of their opinions," as the court ruled in a recent New Jersey case.
Integrity of Specimen
Opposing expert witnesses try to raise doubts about the way DNA evidence was gathered and tested claiming that contamination may have occurred. The usual argument is that the underlying procedures for forensic DNA testing were developed in laboratories where pure and known samples were used and retesting always was an option. While this is true, the argument doesn't mention the usual results of contamination, the ease with which it can be detected, and the safeguards that are in place in most forensic DNA labs.
In almost all cases, the results of using a specimen sufficiently contaminated to alter test results simply would be ruled inconclusive. One way a specimen might be contaminated is by genetic material from the technician performing the analysis or from the person gathering the evidence. Again, this could not possibly harm the accused as an exclusion would be the result of such mishandling. Finally, there is the possibility that some of the DNA drawn from the suspect could be accidentally mixed with DNA retrieved from the crime scene. Such an accident would yield false results, especially if PCR amplification is used. To avoid this possibility, crime labs that perform PCR do it in isolation and under stringent conditions that minimize the risk of contamination.
DNA analysis is undeniably better than other tests in analyzing mixed specimens and overcoming a variety of contaminants. Because of its structure and relative stability, DNA can be tested even after mixture with acids, bases, gasoline, oil, or bleach.
Error Rate