EvidenceProf Blog

Editor: Colin Miller
Univ. of South Carolina School of Law

Tuesday, February 26, 2008

The Moment Of Truth: New Mexcio Is The Only State That Finds Polygraph Results Presumptively Admissible

Justin Black's murder trial for his alleged strangulation of Deanna L. Crawford is the latest trial to end in a mistrial after a prosecution witness made reference to a polygraph examination taken by the defendant.  This was going to lead me to write that all states have deemed polygraph results inadmissible unless both parties agree before the test that the results will be admissible at trial, but I wanted to make sure that such a statement was accurate.  It turns out that it is not because New Mexico does allow for the admission of polygraph results.

In 1973, the Supreme Court of New Mexico found in State v. Dorsey, 539 P.2d 204 (N.M. 1975), that polygraph results are admissible as long as (1) the polygraph operator is competent, (2) the procedure used is reliable, and (3) the “tests made on the subject” are valid.  In 1983, New Mexico then codified the admissibility of polygraph results with Rule of Evidence 11-707, which states, inter alia, that

"Subject to the provisions of these rules, the opinion of a polygraph examiner may in the discretion of the trial judge be admitted as evidence as to the truthfulness of any person called as a witness if the examination was performed by a person who is qualified as an expert polygraph examiner pursuant to the provisions of this rule and if;

     -(1)  the polygraph examination was conducted in accordance with the provisions of this rule;

     -(2)  the polygraph examination was quantitatively scored in a manner that is generally accepted as reliable by polygraph experts;

     -(3)  prior to conducting the polygraph examination the polygraph examiner was informed as to the examinees's background, health, education and other relevant information.

     -(4)  at least two (2) relevant questions were asked during the examination; and

     -(5)  at least three (3) charts were taken of the examinee."

Up until the Supreme Court of New Mexico's 2004 decision in Lee v. Martinez, 96 P.3d 291 (N.M. 2004), however, the Court had not yet determined whether polygraph results met the standard for the admissibility laid out in Daubert in 1993 and subsequently incorporated into the New Mexico Rules of Evidence.  As applied in New Mexico, the test asks whether (1) whether the theory or technique “can be (and has been) tested”; (2) “whether the theory or technique has been subjected to peer review and publication”; (3) “the known potential rate of error” in using the particular scientific technique “and the existence and maintenance of standards controlling the technique's operation”; and (4) whether the theory or technique has been generally accepted in the particular scientific field." State v. Anderson, 881 P.2d 29, 36 (N.M. 1994).

With regard to (1), the court found that the control question polygraph examination can be tested based upon a National Academy of Sciences Report.  With regard ro (2), the court noted that the NAS report included 102 studies deemed to be of sufficient quality.  With regard to (3), the court noted that "a number of polygraph validation studies have been conducted and subsequently published. A review of those studies revealed that the median accuracy index of the polygraph in laboratory studies is 0.86 with an interquartile range of 0.81 to 0.91.  Finally, with regard to (4), the court found that "[t]he American Polygraph Association (APA), the leading polygraph professional association, has developed protocol standards for the polygraph similar to those contained in Rule 11-707.

Even with the data reported by the Supreme Court of New Mexico, I'm still not quite convinced that polygraph results are reliable enough to be admitted to jurors, who might overvalue those reults.  That said, I would be very interested in studies looking at convcition rates, later reversals basd upon DNA evidence, etc. in New Mexico compared to those rates in other states.  Such data might leave me a skeptic or turn me into a true believer.



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