A science-based blast at Prosecutors’ belief in alchemy, voodoo and bitemarks

The Current Issue

Oxford University Press’  Journal of Law and the Biosciences just published an amicus curiae (i.e. friend of the court) anti-bitemark treatise which empirically debunks the recent PCAST deniers such as the National DA Association, the IAI, a ‘congress’ of crime labs, the US Department of Justice and the FBI.

The treatise does a complete look into skin-pattern-matching origins, early case law of its acceptance, judicial scientific mis-conceptions about validity, self-serving assumptions, dozens of exonerations, and ruinous failures in proficiency testing. The parallels to alchemy and voodoo are striking. Recent research into the impossibility of bitemarkers possessing ‘medical certainty’ in court gets special attention.

NOTE: the use of ’empirical’ should be considered facts, peer-reviewed studies, failed reliability testing and data underscoring the false beliefs advertised by the bitemark dentists belonging to the American Academy of Forensic Sciences. Read about the ‘Bullshit Factor about Bitemarks.’

Here are the curiae’s panel members. amicus-curiae The entire brief puts the scientific method’s objectivity up against sniveling, mis-facts and innuendo that has appeared in the media from DAs such as San Bernardino’s (CA) Michael Ramos.

Forensic bitemark identification: weak foundations, exaggerated claims (treatise)

An excerpt:

[explaining the latest 2015 proficiency testing disaster of the bitemarkers]

Taking all three questions together, for just under half of the cases, half or fewer of the examiners agreed on the same trio of responses. For only 14 of the 100 cases, did at least 80 per cent of the examiners agree on the trio of responses.

Although no one knows which answers of which examiners were correct or not (the validity question), one can be sure that many answers were incorrect since contradictory answers cannot all be correct. The reliability of a measuring instrument sets an upper limit on its possible validity.

The study just described suggests that on this earliest threshold issue—before any of the other difficulties of bitemark ‘comparison’ have to be confronted—bitemark analysis has not been shown to be reliable (let alone valid). Put simply, if dental examiners cannot agree on whether or not there is enough information in an injury to determine whether it is a bite mark, and cannot agree on whether or not a wound is a bite mark, then there is nothing more they can be relied upon to say. Unless and until they can do this threshold task dependably, there is no other aspect of bitemark identification that can be counted upon to produce dependable conclusions.

About csidds

Dr. Michael Bowers is a long time forensic consultant in the US and international court systems.
This entry was posted in AAFS, ABFO, Bite Marks, forensic science reform and tagged , , , , . Bookmark the permalink.

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