Anthropology 2235A/B Lecture Notes - Voir, Exclusionary Rule

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Published on 2 Jul 2012
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Lecture 31 Forensic Casework
Everything begins at the crime scene
Different specialists have different skills
In order for an evidentiary item to have probative value relative to an
exemplar sample, must establish ‘context’ and ‘continuity’
Continuity begins at the crime scene and ends in court
o Keep track of evidence throughout the investigation
Always have to assume a case will go to court
Each technique has its own approaches to individuation
o Qualitative vs. quantitative assessment
Expert Witness Testimony
o Our system is adversarial, also controversial
o Under Daubert new criteria for admissibility
o Judge is the gatekeeper
Decision maker on what is and is not shown in court
o Legally trained minds value testimonial evidence and trust vigorous
cross examination to expose its weaknesses
o CSI effect in court
o Lawyer speak and science speak are world’s apart
Lawyers trained to manipulate words
Expert Witness Testimony from Daubert Recommendations and Rules
of Engagement
o Continuity of known (exemplar) and unknown (evidentiary) samples
o Disclosure (the scientific paper trail)
o The qualifications of the expert (papers, courses, professional
o Presenting evidence in court
o Voir dires
o Reliability of the laboratory and the expert
o Meaning of statistics
o Significance of the evidence in a particular case (scientific vs.
In Canada: R. v. Mohan
o Four criteria upon which the admission of expert evidence depends:
1. Relevance (science, cost benefit analysis)
2. Necessity in assisting the trier of fact
3. Absence of any exclusionary rule
4. Properly qualified expert
Issues whenever science is used in courts
o Admissibility (voir dires), reviewed by trial judge not a jury
o Chain of custody
o Relative weight given the evidence once it is submitted
o Qualitative vs. quantitative weight
The Expert
o Court has to approve the expert (must show evidence of
competence in the methodology and must have publications in peer
reviewed journals)
o Standard questioning of credentials etc by Daubert
o Often the expert did not actually run the tests so there are
questions about the lab and accreditation
o Often there are errors in stating the significance of a match and the
judge or defense counsel can ask questions that can elicit an
incorrect response (prosecutors fallacy)