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HISTORY


ESTABLISHING SCIENTIFIC EVIDENCE IN THE UNITED STATES

Scientific evidence follows a predictable pattern. There are three "wise men" that need to be called to establish scientific evidence: the Educating, Reporting and Interpreting (ERI) expert witnesses.


EDUCATING WITNESS


Role

The educating witness teaches fact-finder (jury or, in a bench trial, judge) about the underlying scientific theory and instrument implementing theory. This witness is an expert witness, called to elicit opinions that a theory is valid and the instruments involved are reliable. The witness must be accredited as an expert witness, which may require academic qualifications or specific training.
  • Judicial Notice: may moot the need for this witness.

  • Qualifications: Relative experience based on complexity and subtlety of the subject-matter. This witness is on high plane of abstraction about the validity and reliability.

  • Validity of Theory: Most jurisdictions require the theory used by an expert witness to meet certain qualifications before being used in court. The two most common are the Daubert and Frye tests.



Frye Test

The Frye Test calls for a theory to be generally accepted in scientific community.

This test results in uniform decisions regarding admissibility.

This test has been criticized as misunderstanding the scientific process and being based on the assumption that a jury is unable to evaluate scientific testimony.


Daubert Test

The Daubert test arose out of the case Daubert V. Dow Chemical, 509 U.S. 579 (1993) . It requires four things to be shown:
  • (1) Whether theory will help fact-finder (That is, whether the theory has or can be tested)

  • (2) Whether theory has been peer reviewed (This is a component of good science and will improve likelihood the flaws will be found.)

  • (3) Whether the theory has a significant rate of error

  • (4) Whether the theory is is "generally accepted (not required but it helps to know scientific community approves.)


The Federal Rules Of Evidence use the Daubert Test. See FRE 702 .


REPORTING WITNESS

Reporting Witness: Called after teaching witness leaves stand. Usually the laboratory tech. who personally conducted the test. Witness will describe both the test and the results. When describing test, will venture opinions that proper test procedures were used and that equipment was in good working order.
  • Whether witness is qualified to conduct test. Could qualify as expert by virtue of "skill" gained through "experience & training" (FRE 702)—usually experiential, on-the-job training.

  • Whether witness received the correct object to be tested. (Chain of Custody satisfying FRE 104(b)).

  • Whether instrument(s) involved were in proper working order.

  • Proof test procedures were used. This split the courts, but under CL, most Jx require foundational proof that the witness used proper test procedures on the occasion in question.

  • Statement of Test Result: witness says what the results were. Excellent place to put physical evidence. Remember, validating scientific evidence raises a logical relevance issue, as does the authentication (e.g. with enlarged photo).



INTERPRETING WITNESS

Interpreting (Evaluating) Witness: Sometimes not needed 1) when test result is self-explanatory or pass-fail, or 2) when there is a statutory presumption obviating the need (e.g. DWI statutes and a test showing > BAL). Otherwise, this witness needed to complete the foundation. Syllogistic in nature: 1) states the interpretive standard (Rule or Major Premise), applies the standard to the test result (minor premise) and derives a conclusion.
  • Qualifications: a hybrid with both academic and experiential qualifications.

  • Will base finding on the Reporting witness. may base opinion on 1) what personally observed, 2) facts that are the type of data customarily considered by practitioners of the specially and 3) hypothetically assumed facts. Ideal if present when Reporter conducted test, but may be permitted in some Jx.

  • Some Jx. won't accept opinion unless "reasonable scientific opinion." Otherwise, need to consider if the witness can couch the opinion in terms of statistical probably—Collins

    • People v. Collins, 438 P.2d 33 (Cal. 1968): Old lady knocked down and robbed by blond who escaped in yellow car with bearded black man. Ds met that rough description but could not be conclusively identified. Prosecutor used a mathematics professor to discuss the probability that this couple could be the guilty party. Lower court overruled D's objection. Ct. held that 1) there was no foundational establishment of the underlying probabilities and 2) the fact that the Ds fit a probability model was irrelevant because it doesn't prove they did it.