Academic journal article Albany Law Review

The Best Insurance against Miscarriages of Justice Caused by Junk Science: An Admissibility Test That Is Scientifically and Legally Sound

Academic journal article Albany Law Review

The Best Insurance against Miscarriages of Justice Caused by Junk Science: An Admissibility Test That Is Scientifically and Legally Sound

Article excerpt

In the past few decades, the American criminal justice system has had to come to terms with the reality that wrongful convictions are not exceedingly rare occurrences. By 2017, post-conviction DNA testing had established the innocence of over 340 wrongfully convicted accused. (1) The National Registry of Exonerations lists almost 2,000 wrongful convictions. (2) It is particularly disturbing that in many cases, flawed or at least overstated expert testimony appears to have contributed to these wrongful convictions. (3) Inaccurate expert testimony is a "recurrent theme 1:1" in the wrongful conviction studies. (4) In one study of 156 accused later exonerated by post-conviction DNA testing, during at least 60 percent of the trials, "forensic analysts called by the prosecution provided invalid testimony.... [including] the misuse of empirical population data and... conclusions regarding the probative value of evidence that were unsupported by empirical data." (5) Researchers have faulted erroneous opinions by forensic experts in a wide range of fields, "including blood serology, hair evidence, soil comparison, early DNA tests, bitemark analysis, dog sniffs, spectrographic voice identification, shoeprints, and fiber comparisons." (6)

To be sure, in some cases the miscarriage of justice was virtually unavoidable. In most scientific fields, research is ongoing. At one point in time--the time of an accused's original trial--the available empirical data might have seemed to support the validity of a particular scientific theory or technique. On that assumption, at the trial it is understandable that an honest expert would be willing to testify based on the technique and that a trial judge would admit the testimony. However, as the research evolved, later discovered data might undermine confidence in the technique. No matter how careful early researchers are, it is always possible that the outcomes in their studies will be flawed because, by happenstance, the researchers drew unrepresentative samples from the relevant universe. Unless the researchers conduct a complete census of the universe, any given "random" sample can turn out to be atypical.

Microscopic hair analysis is a case in point. For decades, trace evidence experts testified that based on a detailed comparative microscopic analysis of hair strands found at a crime scene and obtained from an accused, an accused was the likely source of the crime scene strands. (7) DNA experts later developed techniques for analyzing mitochondrial DNA ("mtDNA") in hair. (8) In an F.B.I. study of eighty hair comparisons in which the trace analysts had reported a microscopic match or association, mtDNA analysis demonstrated that nine samples (12.5 percent) came from different persons. (9) In these situations, given the earlier state of the empirical research the prior conviction may have been defensible; but the question that arises later is whether the accused is entitled to post-conviction relief. Some courts have awarded new trials under the existing statutes governing post-conviction relief. (10) In other jurisdictions such as California and Texas, the legislatures have recently amended their statutes to expressly provide relief when later scientific research invalidates a technique or theory that played a major role in securing an accused's conviction. (11)

In other cases, though, the wrongful conviction is avoidable. In these cases, at the very time that the forensic expert took the stand to testify about a technique or theory, there was empirical data demonstrating the invalidity of the technique or theory and the data was reasonably accessible to the accused's defense attorney. On occasion, when the facts are extreme enough to clearly demonstrate the defense attorney's negligence, courts can grant relief based on ineffective assistance of counsel in violation of the Sixth Amendment. (12) However, the optimal solution is to devise and enforce an admissibility standard that separates the wheat from the chaff and prevents the introduction of the junk science. …

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