1 What Is Scientific Evidence? Scientific evidence is most often presented in court by an expert witness testifying on expert opinions. It also includes expert testimony that goes beyond science. The scientific expert is frequently called upon to interpret results and draw conclusions about what results mean in the case being tried.

Functions of the Forensic Scientist Forensic Scientists rely primarily on scientific knowledge. However, only half the job is performed in the laboratory while the other half takes place in the courtroom. These functions fit into three categories:

Admissibility of Scientific Evidence How does the court decide whether or not to accept scientific evidence? The judge and jury are typically not scientifically trained. How does the court decide whether or not to accept scientific evidence? The judge and jury are typically not scientifically trained. Several court cases illustrate the steps in the development of admissibility. Several court cases illustrate the steps in the development of admissibility.

Frye vs. United States (1923) Scientific validity of polygraph is rejected Scientific validity of polygraph is rejected Court ruled that in order to be admitted as evidence in trial the questioned procedure, technique or procedure must be “generally accepted” by a meaningful segment of the scientific community. Court ruled that in order to be admitted as evidence in trial the questioned procedure, technique or procedure must be “generally accepted” by a meaningful segment of the scientific community. Collection of experts called in to testify about the validity of scientific issues Collection of experts called in to testify about the validity of scientific issues Books and papers written on subject reviewed and discussed. Books and papers written on subject reviewed and discussed.

Federal Rules of Evidence (1975): A code of evidence law governing the admissibility of evidence in the U.S. federal court system enacted in A code of evidence law governing the admissibility of evidence in the U.S. federal court system enacted in Rule 702 applies to scientific, technical or otherwise specialized knowledge. Rule 702 applies to scientific, technical or otherwise specialized knowledge. Individual states are free to adopt different evidence rules but most have codes that are based on FRYE. Individual states are free to adopt different evidence rules but most have codes that are based on FRYE.

6 Courts traditionally use one of these rules for the admissibility of scientific evidence: The Frye Test The Frye Test Frye v. United States (1928) 293 F Frye v. United States (1928) 293 F The Frye Test Plus or KELLY-Frye test The Frye Test Plus or KELLY-Frye test People v. Kelly (1976) 17 Cal.3d 24 People v. Kelly (1976) 17 Cal.3d 24 Daubert Test Daubert Test Daubert v. Merrell-Dow Pharmaceuticals, Inc. 509 U.S. 579, 113 S.Ct (1993). Daubert v. Merrell-Dow Pharmaceuticals, Inc. 509 U.S. 579, 113 S.Ct (1993).

7 Frye Standard, Frye v. U.S. 293 F (D.C. Cir. 1923) Essentially, for the results of a scientific technique to be admissible, the technique must be sufficiently established to have gained general acceptance in its particular field. Essentially, for the results of a scientific technique to be admissible, the technique must be sufficiently established to have gained general acceptance in its particular field. This is referred to as the "general acceptance" test by the scientific community. This is referred to as the "general acceptance" test by the scientific community.

Illinois Rules of Evidence Rule 702 TESTIMONY BY EXPERTS 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. Where an expert witness testifies to an opinion based on a new or novel scientific methodology or principle, the proponent of the opinion has the burden of showing the methodology or scientific principle on which the opinion is based is sufficiently established to have gained general acceptance in the particular field in which it belongs. 8

Although there had been considerable clamoring for Illinois to adopt the Daubert test, as the Federal courts and many other jurisdictions have done, the Illinois Supreme Court has made it clear that it is Frye and not Daubert that must be followed. 9

the testimony is based upon sufficient facts or data, the testimony is the product of reliable principles and methods, and the witness has applied the principles and methods reliably to the facts of the case. 10

The Frye test as set forth in Frye v. United States, 293 F (D.C. Cir. 1923), is a specific test of admissibility related to expert testimony concerning scientific evidence. Where opinion testimony is based on the expert’s personal knowledge and practical experience, but not based on “studies and tests,” it is not subject to a Frye test. Donnellan v. First Student, Inc., 383 Ill. App. 3d 1040, 1061, 891 N.E.2d 463 (1st Dist. 2008). The Frye test is also known as the “general acceptance” test, as it requires that “the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs. 11

12 The Daubert Test The court suggested the trial court consider various factors to assess scientific validity The court suggested the trial court consider various factors to assess scientific validity Has the theory been tested? Has the theory been tested? Has it been subjected to peer review by other scientists? Has it been subjected to peer review by other scientists? What is the theory ’ s or technique ’ s known or potential rate of error? What is the theory ’ s or technique ’ s known or potential rate of error? Do standards controlling the application of the theory or technique? Do standards controlling the application of the theory or technique? Is the theory or technique generally accepted? Is the theory or technique generally accepted?

Daubert v. Dow Pharmaceuticals, Inc. (1993) “general acceptance” or Frye standard no longer absolute prerequisite. “general acceptance” or Frye standard no longer absolute prerequisite. Trial judge given the task of ensuring an expert testimony rests on a reliable foundation, is relevant to case, and is not repetitive, inflammatory or unnecessarily confusing. (gatekeeper) Trial judge given the task of ensuring an expert testimony rests on a reliable foundation, is relevant to case, and is not repetitive, inflammatory or unnecessarily confusing. (gatekeeper)

Daubert Ruling suggested areas of inquiry: Whether the scientific technique or theory can be (and has been) tested. Whether the scientific technique or theory can be (and has been) tested. Whether the technique or theory has been subject to peer review & publication Whether the technique or theory has been subject to peer review & publication The technique’s potential rate of error The technique’s potential rate of error The existence and maintenance of standards The existence and maintenance of standards Whether the scientific theory or method has attracted widespread acceptance within a relevant scientific community Whether the scientific theory or method has attracted widespread acceptance within a relevant scientific community

15 Daubert v. Merrell Dow (1993) The Court “ REJECTED ” the more basic Frye test of “ general acceptance ” in the scientific community. The Court “ REJECTED ” the more basic Frye test of “ general acceptance ” in the scientific community. Daubert requires an independent judicial assessment of reliability. Daubert requires an independent judicial assessment of reliability. This test requires special pretrial hearings for scientific evidence and special procedures on discovery. This test requires special pretrial hearings for scientific evidence and special procedures on discovery. This is a more stringent test that requires knowledge of Type I and Type II error rates, as well as validity and reliability coefficients. This is a more stringent test that requires knowledge of Type I and Type II error rates, as well as validity and reliability coefficients.

16 Daubert test requires (federal) judges to ascertain the following: (1) Whether the theory or technique is capable of being or has been tested; (1) Whether the theory or technique is capable of being or has been tested; (2) Whether it has been subjected to peer review and publication; (2) Whether it has been subjected to peer review and publication; (3) The known or potential rate of error in using a particular scientific technique and the standards controlling the technique's operation; and (3) The known or potential rate of error in using a particular scientific technique and the standards controlling the technique's operation; and (4) Whether the theory or technique is generally accepted in the particular scientific field. (4) Whether the theory or technique is generally accepted in the particular scientific field.

Admissibility of Evidence 1923 Frye v. United States  Scientific evidence is allowed into the courtroom if it is generally accepted by the relevant scientific community.  The Frye standard does not offer any guidance on reliability.  The evidence is presented in the trial and the jury decides if it can be used.  Known as general acceptance standard Daubert v. Dow Admissibility is determined by: ý Whether the theory or technique can be tested ý Whether the science has been offered for peer review ý Whether the rate of error is acceptable ý Whether the method at issue enjoys widespread acceptance. ý Whether the opinion is relevant to the issue The judge decides if the evidence can be entered into the trial.

Concerns about the Daubert Ruling: Abandoning Frye’s general acceptance test will result in the introduction of absurd pseudoscientific claims in court Abandoning Frye’s general acceptance test will result in the introduction of absurd pseudoscientific claims in court Supreme Court rejected these concerns: Supreme Court rejected these concerns: The judicial system is capable The judicial system is capable Through vigorous cross-examination, presentation of contrary evidence and careful instruction on the burden of proof are the traditional & appropriate means of attacking shaky but admissible evidence. Through vigorous cross-examination, presentation of contrary evidence and careful instruction on the burden of proof are the traditional & appropriate means of attacking shaky but admissible evidence. Different methods-same results: “Frye in drag”