The Admissibility and Reliability of Expert Evidence

Question 1

What is the trial process directed at?

Answer 1

Answering the question: “What happened?”

Question 2

What type of evidence can a lay witness present?

Answer 2

Direct knowledge

Question 3

What type of evidence can an expert witness provide?

Answer 3

Opinion

Question 4

Can lay witnesses provide opinion-based testimony

Answer 4

In certain circumstances

Question 5

Give an example of a situation in which a lay witness could give their opinion?

Answer 5

Another individual’s degree of impairment

Question 6

What are two key principles regarding witness testimony?

Answer 6

1. There is no property in a witness
2. The trial judge’s decision with respect to the admissibility of expert evidence is entitled to deference.

Question 7

When is an expert needed?

Answer 7

If opinion evidence based in specialized knowledge is required to assist the trier of fact in understanding subject matter beyond common experience

Question 8

What are the two steps involved in expert admissibility?

Answer 8

1. Qualifies under Mohan admissibility criteria test
2. Judge conducts cost-benefit analysis

Question 9

What are the four (plus one) Mohan admissibility criteria?

Answer 9

1. Relevance (logically relevant)
2. Necessity in assisting the trier of fact
3. Absence of any exclusionary rule
4. Properly qualified
5. Underlying science must be reliable for the purpose for which it is sought to be admissible.

Question 10

When does the fifth Mohan criterion apply?

Answer 10

If the opinion is based on novel science or contested science, or science used for a novel purpose.

Question 11

When might logically relevant evidence be excluded?

Answer 11

If…
1. Its probative value is overborne by its prejudicial effect
2. If the time required is not commensurate with its value
3. If it can influence the trier of fact out of proportion to its reliability

Question 12

When should expert evidence not be admitted?

Answer 12

Where there is a danger that it will be misused, distort the fact-finding process or confuse the jury.

Question 13

What are two key admissibility criteria that reflect the trend towards an evidence-based approach in the forensic sciences?

Answer 13

1. Expert’s duty to provide impartial, independent and unbiased evidence
2. The underlying science for opinions based on novel or contested science used for a novel purpose must be reliable.

Question 14

What was established in R. v. Trochym?

Answer 14

The judiciary can rely on the decision of past courts to admit established sciences.

Question 15

Which is more important when deciding expert evidence admissibility: Probative value or prejudicial risks?

Answer 15

Probative value

Question 16

What is the cost-benefit analysis done by the judge for expert witness testimony?

Answer 16

Legal relevance
Necessity
Reliability
Absence of bias

Question 17

What case sets out the difference between logical and legal relevance?

Answer 17

R. v. Abbey

Question 18

What does logical relevance mean?

Answer 18

Evidence has a tendency as a matter of human experience and logic to make the existence or non-existence of a fact in issue more or less likely than it would be without the evidence.

Question 19

What is legal relevance?

Answer 19

Involves a limited weighing of the costs and benefits associated with admitting evidence that is undoubtedly logically relevant.

Question 20

What was set out in R. v. Sekhon in relation to expert witnesses?

Answer 20

The trial judge must:
1. Ensure the expert stays within the proper bounds of their expertise
2. Ensure the content of the evidence is properly the subject of expert evidence.

Question 21

When is bias assessed in a trial?

Answer 21

At both admissibility steps and weight

Question 22

What were the miscarriages of justice associated with Dr. Charles Smith?

Answer 22

Testifying beyond scope
Overstating the evidence supporting his opinion
Being less than impartial in his approach to the analysis

Question 23

What did R. v. France state that it is important for an expert witness to do?

Answer 23

Maintain an open mind to a broad range of possibilities as bias can often be unconscious.

Question 24

Describe the facts of R. v. Mohan

Answer 24

Practicing pediatrician charged with sexual assault x4 with respect to 4 female patients, aged 13-16.
Assaults occurred during medical exams in his office.
Defence counsel intended to call a psychiatrist.

Question 25

What did the psychiatrist testify to in the voire dire of Mohan?

Answer 25

The perp’s profile with respect to first 3 victims was likely that of a pedophile
With respect to fourth, that of a sexual psychopath
Respondent did not fit the above profiles.

Question 26

What was the ruling for the psychiatrist evidence in Mohan?

Answer 26

Inadmissible

Question 27

What was the finding of Mohan after trial?

Answer 27

Guilty

Question 28

What was the issue in question for the SCC appeal of the Mohan case?

Answer 28

In what circumstances is expert evidence admissible to show that character traits of an accused person do not fit the psychological profile of the putative perpetrator of the alleged offences?

Question 29

What did the SCC hold in the Mohan case?

Answer 29

Appeal should be allowed. Evidence should be excluded.

Question 30

Why did the SCC make the decision they did in the Mohan case?

Answer 30

Relevance - Expert evidence was not needed as info was common sense
Necessity - profiles were not sufficiently reliable, any value would be outweighed by its potential to mislead or distract the jury
Exclusionary rule - excluded as part of evidentiary rule excluding character evidence.

Question 31

Which case is this famous quote from: “There is a danger that expert evidence will be misused and will distort the fact-finding process. Dressed up in scientific language which the jury does not easily understand and submitted through a witness of impressive antecedents, this evidence is apt to be accepted by the jury as being virtually infallible and as having more weight than it deserves. …”

Answer 31

R. v. Mohan

Question 32

What are the 4 criteria provided in Daubert v. Merrell Dow Pharmaceuticals regarding reliability of scientific evidence?

Answer 32

1. Theory: testable and tested?
2. Theory: withstood peer review and publication?
3. Application: Known or potential error rate or existing standards to test application?
4. Recognition in scientific community: Has the theory been generally accepted by the relevant scientific community?

Question 33

Is there a definitive checklist when evaluating reliability?

Answer 33

No

Question 34

What was Dr. Pollanen (forensic pathologist) allowed to testify to in R. v. France?

Answer 34

COD and Mechanism of death.

Question 35

What was Dr. Pollanen (forensic pathologist) not allowed to testify to in R v. France?

Answer 35

Whether other injuries made it more likely abdominal injury is caused by assault.
Likelihood of assault v. accidental fall.
Say injury caused by a “significant” blow and cannot use language of “consistent with”.
Hypotheticals should not be so detailed as to mirror the facts of this case.

Question 36

What did the court find in regards to Dr. Pollanen in R. v. France?

Answer 36

1. He failed to properly prepare before testifying and still expressed an opinion with certainty
2. He offered opinions beyond his area of expertise
   3.Professional credibility bias: looked for ways to support a hasty position
3. Confirmation bias: started from position that case was abuse, then looked to prove it.

Question 37

What minimum qualifications must be met before an expert is relied upon?

Answer 37

Accreditation and quality assurance
Training and continuing education
Membership in oversight organizations and relevant academies or associations

Question 38

What are additional qualifications of expert witnesses to consider?

Answer 38

Level of relevant education
Experience
Publications, presentations, research
Supervisory/peer review/education roles
Treatment in case law

Question 39

What 4 steps can an expert take to help ensure their evidence is understood correctly?

Answer 39

1. Be prepared - meet prior to trial
2. Be objective and provide thorough reasoning for their findings
3. Understand that misconceptions of the discipline mat be held by lawyers, the judge and the jury.
4. Be familiar with the case and the courtroom.

Question 40

What concepts should be kept in mind when evaluating expert reliability in the context of a criminal case?

Answer 40

1. Ethical considerations may prevent certain types of research studies
2. Every method has strengths and limitations
3. Hypotheticals may need to be addressed because details in real life will oftentimes be unknown
4. Experts and lawyers/judiciary must effectively communicate
5. Everyone must act within their role for the system to work.