Polygraph vs. the Eye Witness

Eye witness inaccuracy vs. polygraph consistent accuracyWhile nothing in evidentiary rules is probably more hotly contested than the admissibility of the use of polygraph examination results in court, it seems to be more of a bias against machinery than reliability.  For example, typical accuracy of a professional polygraph examiner is about 93%-98% accurate. Compare that to the accuracy of the most highly regarded (and possibly worst) evidence… eye witnesses.

Put ten people in a situation and how many different versions of the same incident will you get? Studies have shown that while valued as some of the most important of evidence, it is often the worst… and yet, polygraph examinations, when consistently performed by a professional can be accurate 95% of the time. Circuit courts have declared that “Polygraphs are NOT unreliable and can be validly used to monitor the post-release supervision of an offender. ”1

The Eye Witnesses were JUST Wrong!

Of the 289 Post-Conviction DNA Exonerations of single perpetrator crimes in the U.S., 216 innocent people went to prison due mistaken eye witness accounts, making it the leading cause of these wrongful convictions. In other words, in these exonerations, 75% of the exonerations involved eyewitness misidentifications. At least 40% of these eyewitness identifications involved a cross racial identification. Studies have shown that people are less able to recognize faces of a different race than their own.2  Of the first 130 exonerations effected by DNA, 100 out of 130 of the convictions were eye witness misidentifications.((<a target=”_blank” href=”http://www.psychology.iastate.edu/~glwells/The_Justice%20Project_Eyewitness_Identification_%20A_Policy_Review.pdf”>http://www.psychology.iastate.edu/~glwells/The_Justice%20Project_Eyewitness_Identification_%20A_Policy_Review.pdf </a> ))

From “Eyewitness Identification: A Policy Review”

Experiments have been conducted in which witnesses were shown a staged crime and asked to identify the culprit from a lineup. The lineup they were shown, however, did not contain the culprit. After the witnesses unknowingly made false identifications, they were then asked their level of confidence. Before doing so, however, some of the witnesses were given various types of reinforcing feedback. Those witnesses who received some confirmation of their false identification, whether the information that a co-witness identified the same individual or some other confirming feedback, were far more confident in their identifications than other witnesses who were given no feedback — despite having given false identifications. These witnesses also distorted and exaggerated certain details, such as how good their view was, how much of an opportunity they had to view the culprit, etc.”3

Eye Witness misidentification is so rampant that in November 2002, Justice I. Beverly Lake created the North Carolina Actual Innocence Commission to study and recommend potential strategies for lessening the incidence of wrongful convictions.


While clearly, eye witnesses reporting seems to vary from witness to witness and can be inaccurate, polygraph maintains a consistent accuracy and growing acceptance. Fifth Circuit, U.S. Court of Appeals, reversed a ruling that polygraph evidence is per se inadmissible. Citing advances in the reliability of polygraph techniques, they would allow polygraph evidence in certain circumstances.4 A divided Louisiana Supreme Court allows polygraph evidence in police disciplinary hearings. And in this case, U. S. Supreme Court declined to review it.5

If you would like to discuss the professional services of a polygraph examiner, please contact The Polygraph Examiner at 1-800-497-9305.

  1. U.S. v. Johnson, 446 F.2d 272 (2nd Cir. 2006). []
  2. <a target=”_blank” href=”http://www.innocenceproject.org/Content/Facts_on_PostConviction_DNA_Exonerations.php”>http://www.innocenceproject.org/Content/Facts_on_PostConviction_DNA_Exonerations.php </a> []
  3. <a target=”_blank” href=”http://www.psychology.iastate.edu/~glwells/The_Justice%20Project_Eyewitness_Identification_%20A_Policy_Review.pdf”>http://www.psychology.iastate.edu/~glwells/The_Justice%20Project_Eyewitness_Identification_%20A_Policy_Review.pdf </a> []
  4. U.S. v. Posado, 57 F.3d 428 (5th Cir. 1995). {N/R} []
  5. Evans v. DeRidder Mun. Fire and Police Civ. Serv. Bd., #01-C-2466, 815 So.2d 61, 2002 La. Lexis 962; cert. den., 2003 U.S. Lexis 636 (2003). [2003 FP Mar] []