Opinion Evidence Flashcards
Opinion evidence exclusionary rule
The Exclusionary Rule
● Presumptive inadmissibility of opinion evidence
● Witnesses are to testify what they perceive not their opinion - concern of misleading trier of fact
When is lay witness opinion evidence admissible?
● Instances where lay witness opinion evidence is admissible:
○ they are in a better position than the trier of fact to form the conclusion
○ the conclusion is one that persons of ordinary experience are able to make (common knowledge)
○ the witness, although not an expert, has the experiential capacity to make the conclusion
○ compendious statement of facts that are too subtle or complicated to be stated individually
No opinions on…
● No Opinions on Questions of Pure Domestic Law
● The Rule against Oath-Helping
○ evidence is admissible if it is RELEVANT TO credibility
○ evidence is inadmissible if it is ABOUT credibility
** The Ultimate Rule Issue [old]
○ the closer it gets to a witness stating an opinion/conclusion on the ultimate issue, the more likely it should be excluded
○ no longer a part of Canadian doctrine
Considerations for expert witness opinion evidence (list)
● Necessity - Where likely to be outside the experience and knowledge of the trier of fact, making the expert necessary to assist the trier of fact with making the necessary inferences.
● *Relevance - A specialized probative value vs. probative effect analysis. Assesses benefits vs. costs.
● Properly Qualified Status - special knowledge and experience going beyond that of the trier of fact. (Determined during a voire dire) → ex. education, training, experience, peer reviewed publications.
● Not subject to any other exclusionary rule (ex similar fact evidence, oath helping, hearsay, credibility etc)
*note: in textbook, Abbey adds to Mohan case - gives 2 types of relevance. One is a precondition to admission which means logical relevance to a fact in issue. The second occurs after all the other factors are met and involves the cost/benefit analysis. “Logical” vs “legal” relevance.
Explain necessity in the context of opinion evidence
● Necessity - Where likely to be outside the experience and knowledge of the trier of fact, making the expert necessary to assist the trier of fact with making the necessary inferences.
○ Risk that a trier of fact can accept uncritically the evidence of an expert witness - courts accept risk within limits.
○ “Only when lay persons are apt to come to a wrong conclusion without expert assistance, or where access to important information will be lost unless we borrow from the learning of experts.” (R. v. D.D.)
○ ask: a) will the expert opinion evidence allow appreciation of the technicalities of a matter in issue? b) will it provide info outside the experience of trier of fact? c) is trier unlikely to form a correct judgement about a matter in issue if unassisted by the expert (ex battered woman)? (R v KA)
Explain relevance in the context of opinion evidence
● *Relevance - A specialized probative value vs. probative effect analysis. Assesses benefits vs. costs.
○ Benefits (logical relevance of expert testimony, materiality, weight, reliability)
■ Can have relevance to one material issue in a trial, but not another
■ Whether it helps resolve a material issue
■ Greater benefits when there is a stronger foundation of proven facts as foundation for the expert’s opinion
■ More inferences the trier of fact is required to make to reach the conclusion, or the more tenuous/speculative those inferences would be, the more expert evidence may become weaker and more prone to exclusion.
■ Has the expert observed the proper methodologies or protocols? (not mixed, stored right)
● Is the testing methodology established or novel? - Can the scientific testing be verified by another expert? (junk science, outdated)
■ Foundation in established facts?
○ Costs (possibilities of uncritical acceptance by trier of fact, prejudicial effect, practical costs associated with presentation)
■ Too long or too costly to bring into evidence?
■ Prejudicial effect
■ Possibility of uncritical acceptance? (complexity, confusion, impressive credentials?)
■ Is there an unfair advantage given to a party with more resources to hire experts?
What are the benefits to consider under relevance in opinion evidence?
○ Benefits (logical relevance of expert testimony, materiality, weight, reliability)
■ Can have relevance to one material issue in a trial, but not another
■ Whether it helps resolve a material issue
■ Greater benefits when there is a stronger foundation of proven facts as foundation for the expert’s opinion
■ More inferences the trier of fact is required to make to reach the conclusion, or the more tenuous/speculative those inferences would be, the more expert evidence may become weaker and more prone to exclusion.
■ Has the expert observed the proper methodologies or protocols? (not mixed, stored right)
● Is the testing methodology established or novel? - Can the scientific testing be verified by another expert? (junk science, outdated)
■ Foundation in established facts?
What are costs to consider under relevance in opinion evidence?
○ Costs (possibilities of uncritical acceptance by trier of fact, prejudicial effect, practical costs associated with presentation)
■ Too long or too costly to bring into evidence?
■ Prejudicial effect
■ Possibility of uncritical acceptance? (complexity, confusion, impressive credentials?)
■ Is there an unfair advantage given to a party with more resources to hire experts?
Explain properly qualified status requirement under opinion evidence
● Properly Qualified Status - special knowledge and experience going beyond that of the trier of fact. (Determined during a voire dire) → ex. education, training, experience, peer reviewed publications.
○ Need to define scope/nature of evidence as precise as possible to show where witness is qualified
○ Courts have been lenient
○ Lavallee:
■ Expert opinion is admissible if relevant even if based on second hand evidence
■ Second hand evidence (hearsay) is admissible to show the info on which the opinion is based, not as evidence going to the existence of the facts on which the opinion is based
■ Where psychiatric evidence is comprised of hearsay evidence, the problem goes to weight
■ Before any weight is given to the expert opinion, the facts on which it is based must be found to exist.
○ Beland - The opinion of a polygraph examiner is not admissible because it is adduced solely to evaluate the credibility of a witness, which is the role of the trier of fact
Explain the test to be met to admit novel science
Novel Science → Requires the satisfaction of additional legal tests as a prerequisite to admission
1) Must be essential in the sense that the trier of fact will be unable to come to a satisfactory conclusion without the assistance of the expert.
2) Expert evidence based on novel science must be subjected to special scrutiny with respect to its reliability.
a) Tested?
b) Peer Reviewed?
c) Error Rate?
d) General Acceptance?
3) Subject to an even stricter analysis of necessity and reliability where the expert evidence approaches an ultimate issue in the case
4) Even if these tests are satisfied, if the novel theory has been realistically challenged because it has not previously been subjected to close scrutiny, or because base knowledge has been changed, the expert evidence should not be admitted without confirming the validity of the underlying assumptions.
● There’s a difference between scientific reliability and legal reliability
● Treated as novel if it is a new application of pre existing techniques
Explain the issue of expert witnesses and advocacy, and when the expert evidence might be excluded under such rules
Expert Witnesses and Advocacy
● White Burgess Langille Inman v. Abbott and Haliburton:
○ Exclude if court not assured that expert can abide by the duty to be an objective witness when testifying.
○ If expert testifies during voire dire that they are willing to act according to such duty - sufficient.
○ BUT if the other party shows realistic concern re: expert’s willingness to be objective instead of an advocate, the party calling the expert has burden on BOP to show expert witness’ evidence should be admitted.
○ Only in the clearest cases should court exclude expert witness for concern of advocacy/lack of objectivity.
● → sometimes court can use a court ordered expert which mitigates these concerns
Considerations when cross examining/ examing an expert witness
Examining/ Cross examining expert witnesses:
● Trier of fact must determine the extent to which the facts on which it is based have been proven in evidence
● Common to cross examine expert by posing contradictory opinions cited in authoritative works
● To avoid unfairness to expert, the technique can only be used if expert acknowledges they are familiar with the work cited and confirms it is authoritative
● Concern: witness could be able to avoid an inquiry into breadth/depth of knowledge by refusing to acknowledge a study.
Legislation on expert witnesses (need to know principles not sections)
CEA
● 7. Where, in any trial or other proceeding, criminal or civil, it is intended by the prosecution or the defence, or by any party, to examine as witnesses professional or other experts entitled according to the law or practice to give opinion evidence, not more than five of such witnesses may be called on either side without the leave of the court or judge or person presiding.
BCEA
● s. 11(b) – 30 days in advance to the other party
○ Note: if you dont plan for this it will probably cause an adjournment and you will be left w costs
BC Rules of Court
● Rule 11 – Requirements for Expert Witness Report
Criminal Code
● 657.3 (1) In any proceedings, the evidence of a person as an expert may be given by means of a report accompanied by the affidavit or solemn declaration of the person, setting out, in particular, the qualifications of the person as an expert if
○ (a) the court recognizes that person as an expert; and
○ (b) the party intending to produce the report in evidence has, before the proceeding, given to the other party a copy of the affidavit or solemn declaration and the report and reasonable notice of the intention to produce it in evidence.
● Attendance for examination
○ (2) Notwithstanding subsection (1), the court may require the person who appears to have signed an affidavit or solemn declaration referred to in that subsection to appear before it for examination or cross-examination in respect of the issue of proof of any of the statements contained in the affidavit or solemn declaration or report.
*sometimes there can be a limit on number of experts allowed.
