Junk Science

In her keynote address at the Unlocking Innocence conference, former Attorney General Janet Reno specifically mentioned junk science as a "major cause of wrongful convictions."  Several speakers made similar mention, and several case histories were provided as examples.  Junk Science in the Courtroom litanies dozens of examples of junk science being used to convict the innocent.  Ms. Reno further noted that many lawyers are not familiar with forensic science and terminology, and do not want to be bothered with it.  But lawyers need to be equipped to identify junk science.  Ms. Reno recommends the creation of a forensic institute which would bring law and science together to eliminate junk science from the courtroom. 

Understanding Rules of Evidence

It is the responsibility of trial judges to keep our courts free of junk science.  But how should a judge decide?  What are the standards?  "In the 1923 case of Frye v. United States, a federal judge refused to admit polygraph results against a criminal defendant because the principles of the polygraph had not yet been "generally accepted" by others in the relevant scientific community" (Source).  "Generally accepted" became the standard, the Frye standard.  However, in 1975 the Congress enacted the Federal Rules of Evidence.

With regard to the admissibility of scientific evidence, Rule 702 states that:

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.

In other words, if a jury would find the testimony of one with specialized knowledge to be helpful, a court may admit it. Following the enactment of Rule 702, many courts rejected the Frye standard of "general acceptance" in favor of the more liberal "helpfulness" standard of Rule 702.

The U. S. Supreme Court helped resolve the division in the lower courts in Daubert v. Merrel Dow Pharmaceuticals, Inc., 509 U. S. 579 (1993), by stating that Frye was no longer the standard governing the admissibility of sceintific evidence. Rather, the court interpreted Rule 702 to mean that scientific evidence may be admitted only if it is relevant to the issue at hand and rests on a reliable foundation.

In order to assist the lower courts in applying Daubert, the Court provided the following list of factors that courts should consider before ruling on the admissibility of scientific evidence:

  1. Whether the theory or technique has been reliably tested;
  2. Whether the theory or technique has been subject to peer review and publication;
  3. What is the known or potential rate of error of the method used; and
  4. Whether the theory or method has been generally accepted by the scientific community. (Ibid)

Junk Science's deadly potential comes from the trust the Courts and the Jurors place in "expert testimony," and generally can't tell a good expert from a bad expert.  The general public seems content with the myth that "paid experts," i.e., experts that are paid to deliver the desired outcome, result only from rich defendants who can afford to pay for such, and that every expert who testifies for the State is well-qualified, highly ethical, and only wants to present the truth. 


Junk Science in Scott Peterson's Trial


In Scott Peterson's trial, we have two clear cases of junk science used to convince the Jury of critical "facts" -- facts without which the State had no case.  As with other appeals issues, the determining factor is the importance of the expert testimony to the State's case.  In each of these instances, correct facts would have undoubtedly resulted in an acquittal.


Each of these expert witnesses is well-qualified in his field, but not in the specific area of his testimony.  Each is well published in his field, but not in the specific area of his testimony. 

3Dr. Ralph Cheng.  His expert testimony connected the location of the bodies to Scott's fishing trip, the most critical element of the State's case.  Cheng's analysis is seriously flawed:

3Dr. Greggory Devore.  His expert testimony established Conner's death date within the necessary time frame 8:30 p.m. on the 23rd to 10:08 a.m. on the 24th.  His expert opinion is seriously flawed: