-
Note the potential for opinion evidence regarding someone’s credibility or character – opinion evidence is not containable in its own separate box
Graat v. R. (1982) (S.C.C.) -
Opinion evidence is any inference from primary observed fact
-
“Except for the sake of convenience there is little, if any virtue in any distinction resting on the tenuous and frequently false antithesis between fact and opinion. The line between fact and opinion is not clear.” I.e. it’s a judgement call in any particular case.
-
Some cases will be easy: e.g. “the light was red / she had bloodshot eyes / she was staggering” is primary observed fact, whereas “she was drunk / he was driving very fast / having difficulty driving due to alcohol” is opinion
-
But what about: “Mary was angry / agitated / sweating”. Ask: what makes you think Mary was sweating – you see wet skin (that is perhaps the fact), and you infer she is sweating (maybe it’s raining).
-
A single witness may give a mix of primary observed fact and opinion evidence e.g. a doctor first testifies as to what they saw (“the victim’s leg was bent sideways”) then an expert opinion (e.g. a diagnosis or prognosis)
Concerns with Opinion Evidence
-
Concern 1: Purpose of witnesses is to testify to primary observed facts, inferences to be drawn from those facts is the job of the jury, and don’t want the trier of fact usurped by witnesses
-
Concern 2: reliability issue: anyone can have an opinion, can’t perjure yourself giving it, and can’t be effectively cross-examined over it
-
Concern 3:
-
Jury might be beguiled / unduly impressed by expert opinion evidence, simply accepting it’s ready made inferences as true, and trial degenerates into a fight between experts (“trial by expert”)
-
Also the two sides in a case may have very differing resources to pay experts, leading to unfairness
Turning point for recognizing this concern was Béland, R. v. (1987) (S.C.C.) which made all polygraph testing inadmissible for any purpose
-
Old exclusionary rule (as with old rule against hearsay): opinion evidence is inadmissible, with exceptions, two of which were (which are still useful memory aid, and admissible opinion evidence still fits into one or the other of these):
-
Admissible non-expert / lay witness / compendious statement opinion evidence
-
Admissible expert opinion evidence
-
Current approach: principled, flexible (looking at offer in particular case), no starting point as inadmissible – can improve justice at cost of predictability.
Non-Expert / Lay Opinion Evidence -
Really a rule against speculating where the witness has no real personal knowledge – the more vague the opinion is, the more likely it will be excluded
-
However, cannot truly separate fact from opinion – the more closely tied the opinion is to the facts of the case, the more likely it will be admissible.
-
Leading case is Graat v. R. (1982) (S.C.C.) - non-expert / lay opinion evidence is admissible if two criteria are satisfied:
-
Matter about which person is offering is within common knowledge or experience i.e. does not require expertise.
-
E.g. age, the car looked old, was travelling fast, she looked tired.
-
Will depend on the particular community e.g. in area without bank machines lay person’s opinion about them will not be admissible, nor will city persons opinion on speed of snow-shoeing
-
And either:
-
The opinion will be helpful to trier of fact (which tends to be fairly low hurdle to meet since other side can cross-examine) or
-
It is a compendious statement of fact i.e. (as in this case) it’s the only way the witness can give his/her story i.e. as a bold assertion
-
E.g. witness testifies that someone was drunk, but cannot provide any more details / primary observed facts (i.e. no testimony about odour of breath, ability to walk, etc.), perhaps because at the time they weighed the facts, came up with an opinion, then forgot the facts. This kind of evidence will likely carry little weight after cross-examination.
Expert Opinion Evidence -
E.g. what size scalpel for appendectomy, how properly build a bridge, etc. i.e. doesn’t have to be a doctor or PhD, but expert opinion does have to be outside of normal common knowledge
-
When counsel presents an expert witness, they will usually ask them hypothetical questions, such as “assume a man had 18 beers, would he have capacity to form intent to murder?”
-
Note other side can cross-examine your expert witness, and likely to ask questions to bring up inconsistencies and qualifications, and to question credibility such as are you being paid for giving your opinion, do you do this a lot and if so do is your opinion always for one side,
Mohan, R. v. (1994) (S.C.C.) -
Facts: paediatrician charged with sexual assault on patients. Psychiatrist experts called by defence said some offences consistent with pedophile and others with sexual psychopath, and in our opinion the accused does not fit the profile of either (i.e. expert opinion about accused’s character, that they were not the type of person to do such things)
-
Decision Sopinka J unanimous: evidence is inadmissible due to problems of reliability and that it might beguile the jury.
-
Test, and now always repeated mantra (called the “Mohan necessity and reliability analysis” or the “Mohan 4-step test”, but not so clear and perhaps S.C.C. was trying to shoehorn into the Smith hearsay analysis): the admissibility of expert opinion evidence is determined according to the variable application of four criteria
-
Necessity in assisting the trier of fact - likely to be outside the knowledge and experience of the judge and the jury
-
“Relevance” rather relevant and reliable, like threshold reliability in hearsay analysis)
-
Essentially a cost-benefit analysis
-
A properly qualified expert – can acquire expertise through experience as well as academic training/certification
-
The absence of any exclusionary rule that would be offended by the admission of he opinion (this is superfluous, and was only listed in the case since the evidence in question in this case was also character evidence)
Comment: suggested better way to organise this is:
-
The evidence must be necessary i.e. expertise is required since info is beyond common knowledge or experience
-
J-L. J. (2000) (S.C.C.) – if novel science (see below), must be essential i.e. unable to come to a reasonable decision without the expert evidence (so not just necessary)
-
Necessity is more than just helpful, and dangers of opinion evidence not to be merely tolerated
-
The particular witness offering the opinion must be qualified in the area i.e. an expert
-
Witness has to be satisfactorily qualified, but doesn’t restrict to only Dr’s, PhD’s, engineers, etc., can include anyone with special knowledge/expertise beyond common knowledge e.g. someone with special knowledge of illegal drug business
-
Look at experience, recognition by peers, books, papers, etc. to decide if sufficiently expert
-
Of course want the best most-specialized expert witness, but that can cost a lot, and court will recognize limited resources of parties to hire the best and err on the side of qualifying witnesses as experts
-
The evidence must be not just relevant, but also reliable
-
Concerned with the danger that the trier of fact will be beguiled / unduly impressed by the expert evidence, so judges have responsibility to be gatekeepers and to caution the jury from being overly impressed (note prior to this case expert evidence just had to be helpful, so adding this requirement goes against current move to letting things in and letting jury decide what weight to give)
Novel Science -
Focus in Mohan was on “novel science” or “junk science” – discretion is still upon the judge to accept or reject the expert opinion
-
Novel science = anything new, not mainstream i.e. not generally accepted by experts in the field e.g. a new way to perform an operation, a new theory
-
Concern: how to separate good novel science from mere quackery / mad scientist, which can be difficult.
R. v. Trochym (2007) (SCC)
-
Facts: Important evidence in the case against Trochym was obtained after a neighbour underwent hypnosis and remembered that she had witnessed Trochym leaving the victim's apartment hours after the murder.
-
Issue: Question of expert evidence since issue of whether hypnotism itself was reliable.
-
Held: evidence obtained through hypnosis should not be used in criminal cases because testimony based on such evidence is not "sufficiently reliable" in a court of law.
-
Because the use of hypnosis as a forensic test doesn’t meet the Mohan test, afraid the hypnotism itself may taint the witness and they will not be able to testify on the case
-
Majority applied the J.(J.L.) test for a reliable foundation for novel science evidence:
-
Can the technique be tested and has it been tested?
-
Has the technique been subject to peer review and publication?
-
What is the potential rate of error?
-
Has the technique been generally accepted
-
Essentially the old American test from Frye: expert opinion on science is admissible if that science / technique / theory is generally accepted in the relevant discipline (i.e. peer analysis)
Ultimate issue rule:
-
Old rule: opinion evidence (lay or expert) cannot be given on an ultimate issue (i.e. issue at core of the litigation). Rule reflected concern about “trial by expert”.
-
Rule has been clearly rejected:
-
Rule doesn’t apply with respect to lay opinion: Graat
-
Rule doesn’t apply with respect to expert opinion: Burns (1994) (S.C.C.) and Mohan
Use of textbooks / experts previous writings:
-
Direct / examination in chief of your own expert witness:
-
Can elevate / beef up your expert witness’ opinion by getting their opinions on books written by other (better / more prestigious) experts in the field.
-
Must first ask your expert witness if they find the book authoritative, and if so, you can read passages and ask your expert witness if they adopt that statement.
-
Courts allow this, partly as recognition that funds are limited (and so can’t call the textbook writer) and your expert can then be cross-examined on it.
-
Cross examination of other side’s expert witness:
-
Can use books to confront expert’s opinion
-
First ask expert witness if they find the book authoritative and relevant:
-
If not, that’s the end of the matter (judge won’t let you badger the witness) (Marquard)
-
If they do, can try to get, for example, qualifications
-
Opposition would then be required to bring their own expert to get this other theory or opinion before the court.
-
When calling or cross-examining expert witnesses look into their previous writings, to find out if their opinion has changed significantly / repeatedly / or if there are inconsistencies. With your own witness may want to address a significant change to explain why. On cross-examination with other side’s witness, may be able to use this to question their credibility.
Problem in Abbey
Abbey sets out more restrictive conditions for the use of expert evidence than did previous decision. Four propositions – if true, then if there is no independent evidence, then inadmissible and completely irrelevant:
-
An expert opinion is admissible if relevant, even if it is based on a second-hand evidence.
-
This second hand evidence (hearsay) is admissible to show the information on which the expert opinion is based, not as evidence going to the existence of the facts on which the opinion is based.
-
Where the psychiatric evidence is comprised of hearsay evidence, the problem is the weight to be attributed to the opinion
-
Before any weight can be given to an expert’s opinion, the facts upon which the opinion is based must be found to exist.
Appears to be a spectrum of how much underlying factual basis needs to be established by admissible evidence before putting weight on the export opinion, according to how inherently reliable / contentious is the underlying factual basis:
-
Abbey – need admissible evidence to establish entire underlying factual basis before putting any weight on expert opinion of accused’s insanity (based on hearsay from accused) – here accused and his mother were telling stories to doctor, but in accused’s interest to sound insane to doctor, so perhaps factual basis inherently unreliable
-
Lavallee – so long as some admissible evidence established some of the underlying factual basis, can put weight on expert opinion about battered wife syndrome (but requires warning from judge that the less the factual basis is established, the less weight should be given to the opinion evidence) – reliability of wife’s claims of abuse somewhere in the middle, part of it corroborated, not so easily verifiable
-
Sopinka – makes a distinction between:
-
Evidence that an expert obtains from a party to litigation touching a matter directly in issue (as in Abbey)
-
E.g. a psychiatrist questioning a witness/accused – have to trust a single judgment that the testimony is true
-
Evidence that an expert obtains and acts upon within the scope of their expertise
Hypothetical Questions
-
When counsel presents an expert witness, they will usually ask them hypothetical questions, such as “assume a man had 18 beers, would he have capacity to form intent to murder?” (which is good trial practise since also allows you to submit your theory of events to the jury).
-
Have to know the assumptions that the expert is making
-
Was the opinion is based on that assumption?
-
How many of those assumptions were established in evidence?
-
As you go through the hypothetical questions, the weight of the opinion will vary depending on to the extent with which the assumptions on which the opinion is based have been proven in the evidence.
-
Bleta - However, trial judge has discretion to require counsel to elicit expert’s opinion from hypothetical question to ensure that underlying factual basis on which expert’s opinion is based is clear to the jury
Exchange of Expert Reports
-
Provisions like BC Supreme Court rule 40A – requires you to give 60 days notice to the other side of expert reports that you would like to file
-
Also requires you provide 60 days notice of calling an expert witness
-
Other side can cross-examine that they be able to cross-examine the witness
-
R.40A(1): rule 40A governs the admissibility of expert evidence in conventional trials.
-
R.40A(2): a written statement setting out an expert’s opinion is admissible provided that all parties of record have received a copy of the statement at least 60 days prior to the trial.
-
R.40A(3): the same requirements apply for the admissibility of expert oral testimony.
-
R.40A(5): a written statement by an expert must include reference to the expert’s qualifications and any facts or assumptions on which the opinion is based
-
R. 40A(9),(10),(11): the party against whom the evidence is tendered may require the expert to attend at the trial for cross-examination.
s. 7 CEA: cannot bring more than 5 experts to support your case
Share with your friends: |
