Brian Campbell
July 2003
Challenging the Expert Witness
Introduction
1.
During the last 25 years in my practice of civil and public law litigation, the role of expert
witnesses has come to assume a predominant position in terms of their ability to
determine the outcome of a case because of the strength of their opinion evidence.
2.
Expert witnesses are routinely retained by both parties to provide expert evidence which
pertains to the subject and/or issues at hand, and to provide opinion evidence which
would, but for their expertise be inadmissible. All too frequently the opinion evidence
given by experts pertains to the very issues that are before the trier of fact whether it be a
judge or a jury. In other words, the court hears opinions and conclusions from experts
which formulates the evidence which in turn determines the outcome of the case.
3.
In my view expert witnesses provide at least two important functions which explain their
importance in civil litigation today.
(a)
They provide their expert knowledge to educate the court and to explain to the
court complex, scientific or technical evidence which lay people to not
normally know or understand.
(b)
Secondly, expert witnesses provide opinion evidence in order to persuade the
court that the inferences to be drawn from the evidence which they give,
should be determinative of the issues addressed by the expert in his or her
testimony.
4.
It has been my experience that given the prominence of expert evidence in today’s
litigation the “fact finding” function of the judge or jury has to a significant extent been
subordinated to the function of “selecting” the evidence of the most persuasive of the
experts that appear before the courts.
5.
It is axiomatic that neither a judge nor a jury can know the technical and scientific
information that an expert knows and understands. The Court as the finder of fact does
not have the expertise to challenge the conclusion which may be made by expert
witnesses when deciding which evidence to accept and which to reject. In cases of a
judge alone, the problem may be compounded by the fact that the judge may be asked to
rule on the admissibility of the evidence at the outset of trial.
6.
In the case of R. v. J-L.J. 2000 SCC page 51. Binnie J. states at paragraph 25 as follows:
“Expert witnesses have an essential role to play in the courts. However
the dramatic growth in the frequency with which they have been called
upon in recent years has led to on-going debate about suitable controls on
their participation, precautions to exclude “junk science”, and the need to
preserve the role of the trier of fact – the judge or the jury. The law in this
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regard was significantly advanced by Mohan supra, where Sopinka J.
expressed such concern at paragraph 21:
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. …”
“There is also a concern inherent in the application of this criterion
that experts not be permitted to usurp the functions of the trier of
fact. Too liberal an approach could result in a trial’s becoming
nothing more than a contest of experts, with the trier of fact acting
as a referee in deciding which expert to accept.”
7.
It is my submission that the responsibility of counsel who are presenting the case
becomes extremely important, because they must not only present the evidence but
challenge the opposing expert through cross-examination as to his qualifications and his
evidence so as to provide the trier of fact with the ability to realistically assess the
evidence in question, without being overwhelmed or overly impressed with it.
8.
The role of counsel in cross-examination is to expose not only the weaknesses of the
content of the expert’s report and viva voce evidence, but to challenge the witness’s
ability to formulate the opinions which he holds and more importantly, to test the
assumptions upon which the opinions are based.
9.
A well conducted cross-examination which both challenges the expertise of the witness,
the assumptions with respect to the expert evidence which led to the opinions and the
relevance of the evidence itself or its reliability may go a long way to demystifying the
evidence which has been given by the expert witness, and thereby provide the judge
and/or jury with the ability to consider the evidence in a more realistic and less
deferential light.
10.
Conversely, unprepared counsel may exacerbate the problems faced by judges and juries
attempting to comprehend scientific or expert evidence and thereby compound the
confusion, by conducting an inadequately prepared cross-examination or failing to
challenge the credentials of the witness or by allowing the expert to elaborate on his
theories, rather than controlling the evidence and focusing upon the weaknesses of such
evidence.
11.
That having been said counsel who deal with expert witnesses must acquire a great many
skills, not the least of which is to comprehend what the expert understands and determine
the weaknesses in that evidence.
12.
This is accomplished by having counsel’s own expert review the report of the opposing
expert to provide counsel with an analysis of that report to assist in the crossexamination.
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13.
Ironically what frequently occurs is that in the “battle of the experts” the expert evidence
may very well neutralize itself to such an extent that it becomes difficult for the trier of
fact to select between competing expert theories, such that the case will often be decided
on other evidence in order to resolve the disputes. In other words both experts have
provided such plausible yet dramatically opposed theories or explanations in their
evidence that the trier of fact cannot select which one is preferable and is obliged to
determine the case on another basis.
14.
However, what is far more likely is that the triers of fact must choose between two
competing expert witnesses; therefore, it is critical for counsel to ensure that the expert
opinions that are going to adopted as fact are those of his or her witness rather than those
of his or her opponent.
15.
Therefore in the cross-examination of expert witnesses counsel must not only deal with
the persuasive content of the opponent’s expert report together with their credentials, but
persuade the court that counsel’s own expert should be preferred over that of his
opponent.
16.
To that end the tactic of challenging the expert at an early stage of the proceedings and in
particular at the qualification stage, in my view, is a technique which, although common
place in the U.S.A., is under-utilized in Canada and Ontario.
17.
It has been my experience that at this stage in Ontario at least, there is very little
resistance to the admissibility of an expert’s report or his oral expert evidence, contrary to
what often occurs in cases in the U.S.A., particularly in dealing with controversial
evidence in the soft sciences such as psychological and psychiatric evidence.
18.
In the United States counsel often bring pre-trial motions to challenge the relevance,
authenticity and propriety of expert evidence to be adduced and at this “preliminary”
stage every effort is made by counsel for the party challenging this evidence to have such
evidence ruled inadmissible, and thereby avoid having to discredit the evidence once it
has been received by the Court.
19.
In his article on Junk Science in the United States and the Commonwealth Yale Journal
of International Law (1996) Vol. 21:(2) David Bernstein, commenting on the misuse of
scientific evidence in mass toxic tort litigation (similar to the case in “A Civil Action”)
stated as follows at page 124:
“An even more vociferous debate arose over the alleged misuse of
scientific evidence in toxic tort litigation. Toxic tort cases involve
allegations of injury from exposure to environmental pollutants or
pharmaceuticals …critics began to express skepticism regarding the
evidence relied upon by plaintiffs in many of these causes … plaintiffs’
attorneys often misused scientific evidence in toxic tort cases. Huber
popularized the phrase “junk science” as a description of scientific
evidence that is either inherently unreliable or that is being stretched well
beyond its limitations.”
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20.
It is my theme herein that with the proliferation of expert evidence in civil cases in
Canada, the Courts should be moving towards a stricter set of rules regarding the
admissibility of expert evidence; counsel, in order to anticipate this phenomenon should
be far more willing to challenge an expert’s assumptions and conclusions and deal with
the reliability of expert evidence at the outset, rather than allowing the evidence to stand,
and then cross-examining on its content.
In this paper I will deal briefly with the following subjects.
(a)
What is expert evidence?
(b)
What are the requirements for admissibility of expert evidence in Canada?
(c)
Challenging Expert evidence as to admissibility.
(d)
How to adduce/present expert evidence.
(e)
How to attack the expert.
(f)
Conclusion.
(a)
21.
What is expert evidence?
In the Supreme Court of Canada case of R. v. Abbey (1982) 2 S.C.R. p. 24(3), the Court
described the role of an expert witness as follows:
“With respect to matters calling for special knowledge, an expert in the
field may draw inferences and state his opinion. An expert’s function is
precisely this: to provide the judge and jury with a ready made inference
which the judge and jury, due to the technical nature of the facts, are
unable to formulate. An expert’s opinion is admissible to furnish the court
with scientific information which is likely to be outside the experience and
knowledge of a judge or jury. If on the proven facts a judge or jury can
form their own conclusions without help, then the opinion of the expert is
unnecessary.”
22.
It is asserted that expert evidence is tendered by way of an exception to the rule the
evidence which generally excludes opinion evidence. The exclusion of opinion evidence
is based upon the premise that it would otherwise usurp the function of the trier of fact.
Therefore the existence and proliferation of expert opinion evidence has changed the
landscape as to what is or is not admissible evidence such that nowadays cases are replete
with transcripts of competing opinions from which the triers of fact must make a
selection.
23.
In the case of R. v. A.K. and N.K. (1999) QuickLaw C. 21488 (Ontario Court of
Appeal)(4) the Court dealt with opinion evidence as follows:
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“The opinion rule is a general rule of exclusion. Witnesses testify as to
facts. As a general rule, they are not allowed to give any opinion about
those facts. Opinion evidence is generally inadmissible. Opinion
evidence it generally excluded because it is a fundamental principle of our
system of justice that it is up to the trier of fact to draw inferences from the
evidence and to form his or her opinions on the issues in the case. Hence
it is only when the trier of fact is unable to form his or her own
conclusions without help, that an exception to the opinion rule may be
made and expert evidence admitted. It is the expert’s precise function to
provide the trier of fact with a ready made inference from the facts which
the judge and jury, due to the nature of the facts, are unable to formulate.”
24.
Because expert witnesses provide the Court with the technical and scientific basis upon
which to properly assess evidence, expert witnesses are permitted to testify and provide
the Court with such opinion evidence.
25.
It has been suggested that one of the major functions of experts is to create new evidence
in the form of opinions; this is a unique feature of expert testimony and indeed there is no
other context in which a witness creates new evidence about past events and provides to
the Court a set of opinions that other witnesses do not possess. See: Expert Evidence
(1991) Wisconsin Law Review at page 1140.(5)
26.
Because of the ability of the expert witness to persuade the Court by providing it with
inferences or opinions based upon the testimony the expert gives on complex subjects,
beyond the comprehension of the triers of fact and because the impact of this evidence
can be determinative, I propose to look at what the Courts have done in Canada regarding
the admissibility of expert evidence.
(b)
27.
Admissibility of Expert Evidence in Canada
The leading Supreme Court of Canada case with respect to the determination of the
criteria by which to evaluate whether expert evidence is or is not admissible is the case of
R. v. Mohan (1994) 2 S.C.R. page 20(6) which states as follows:
“Admission of expert evidence depends on the application of the following
criteria:
(i) relevance;
(ii) necessity in assisting the trier of fact;
(iii)the absence of any exclusionary rule;
(iv) a properly qualified expert.”
28.
(i)
Relevance - The Court elaborated on these following four criteria as follows:
“Relevance is a threshold requirement for the admission of expert
evidence as with all other evidence. Relevance is a matter to be decided
by a judge as a question of law. Although prima facie admissible if so
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related to a fact and issues that it tends to establish it, that does not end the
enquiry. This merely determines the logical relevance of the evidence.
Other considerations enter into the decision as to admissibility. This
further enquiry may be described as a cost benefit analysis, that is whether
its value is worth what it costs … evidence that is otherwise logically
relevant may be excluded … if its probative value is overborne by its
prejudicial effect; if it involves an inordinate amount of time which is not
commensurate with its value; or if it is misleading in the sense that its
effect on the trier of fact, particularly a jury, is out of proportion to its
reliability.”
29.
The Supreme Court in Mohan supra in reviewing the Ontario Court of Appeal case of R.
v. Melaragni (1992) 73 C.C.C. (3rd) (348)(7) adopted the relevance test referred to therein
by Moldaver J. as follows:
“1.
Is the evidence likely to assist the jury in its fact finding mission or is it
likely to confuse and confound the jury?
2.
Is the jury likely to be overwhelmed by the “mystic infallibility” of the
evidence or will the jury be able to keep an open mind and objectively assess the
worth of the evidence?”
30.
Therefore the concern of the Supreme Court of Canada was that in deciding whether or
not to admit the evidence, it must be truly relevant and not overwhelm the jury such that
they are intimidated by this evidence and unable to ascertain its usefulness to the case. In
other words there is a fear that the evidence will be incomprehensible to the jury such that
they may feel compelled to adopt it rather than ignore it.
31.
(ii)
Necessity in Assisting the Trier of Fact
The Court in Mohan supra states as follows at page 23 of the decision, regarding the
requirement of necessity.
“This precondition is often expressed in terms as to whether the evidence
would be helpful to the trier of fact. … what is required is that the opinion
be necessary in the sense that it provide information “which is likely to be
outside the experience and knowledge of a judge or jury … the evidence
must be necessary to enable the trier of fact to appreciate the matters in
issue due to their technical nature. … In order for expert evidence to be
admissible the subject matter of the enquiry must be such that ordinary
people are unlikely to form a correct judgment about it if unassisted by
persons with special knowledge.”
32.
As can be seen that the Supreme Court of Canada does not want the expert witness to
assume a larger role in cases than is absolutely necessary such that the expert determines
through his opinion evidence the issues that should be left to the Court.
At page 24 of the Mohan decision the SCC states as follows under this criteria:
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“There is also concern inherent in the application of this criteria that the
experts not be permitted to usurp the functions of the trier of fact. Too
literal an approach could result in a trial becoming nothing more than a
contest of experts with the trier of fact acting as a referee in deciding
which expert to accept.”
In addition the Court states:
“In light of these concerns the criteria of relevance and necessity are
applied strictly on occasion to exclude expert evidence as to the ultimate
issue.”
33.
It has been my experience that this phenomenon of acting as a “referee” selecting one
expert over another is dangerously close to actuality. The evidence can be complicated
which in turn forces the Court to select one expert over the other. In such circumstances,
given the “all or nothing” aspect of evidence selection, the Court may only be guessing as
to the correct evidence it chooses.
34.
Conversely the Court may throw up its hands at competing experts, and reject both
experts, and return to other evidence upon which to base the findings of fact. This latter
result may not be harmful because at least the Court is dealing with what it understands
and may be determining that the expert evidence may not have been necessary.
35.
(iii)
A Properly Qualified Expert
The Court in Mohan supra states at page 25 as follows:
“Finally the evidence must be given by a witness who is shown to have
acquired special or particular knowledge through study or experience in
respect of the matters on which he or she undertakes to testify.”
36.
The Court then goes on to summarize from these foregoing criteria as follows:
“In summary therefore it appears from the foregoing that expert evidence
which advances a novel scientific theory or technique is subject to special
scrutiny to determine whether it meets a basic threshold of reliability and
whether it is essential in the sense that the trier of fact will be unable to
come to a satisfactory conclusion without the assistance of the expert. The
closer the evidence approaches an opinion on an ultimate issue, the stricter
the application of this principle.”
37.
In my submission this means that only when the expert evidence deals with a novel
subject matter or a new science, or the soft sciences, (such as psychology) is attention
paid to its admissibility. It is my view that regarding all expert evidence, far more can
and should be done by counsel on behalf of their clients to challenge the basis of all
expert evidence, whether it deals with the “hard sciences” i.e. engineering or forensic
accounting, or the “soft sciences”, such as psychology, psychiatry. The criteria for
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challenging such evidence is set out in Mohan. It should be utilized more often to test
and to challenge the evidence before it is admitted, into evidence by the Court.
(c)
Challenging the Expert Evidence in Ontario Proceedings
38.
It has been my experience that in the civil litigation milieu judges are not often asked to
screen out or prevent the admission of expert evidence through the application of a
“gatekeeper function” wherein the Court has some obligation to exclude the admission of
irrelevant or non-reliable expert evidence.
39.
Generally speaking it has been my experience that Ontario courts and tribunals will admit
the expert evidence and thereafter determine the appropriate weight to be attached to such
evidence. This may be because the Rules of Civil Procedure do not provide a mechanism
whereby the reliability of expert evidence can be challenged in a formal way prior to trial.
40.
For example, Rule 53.03(2) of the Ontario Rules of Civil Procedure which governs the
admissibility of expert evidence reads as follows:
“A party who intends to call an expert witness at trial shall not less than 90
days before the commencement of the trial, serve on every other party to
the action a report, signed by the expert, setting out his or her name,
address and qualifications and the substance of his or her proposed
testimony.”
Rule 53.03(3) states as follows:
“An expert witness may not testify with respect to an issue except with leave of
the trial judge unless the substance of his or her testimony with respect to this
issue is set out in a report served under the Rules. …” (8)
41.
This test with respect to admissibility simply ensures that both parties get adequate notice
of and exchange of the reports that will be used in evidence by expert witnesses, and
confines the expert’s evidence and his opinions to the content of the reports.
42.
Similarly, in the “Practice Directions” or “Rules of Practice” before countless
administrative tribunals, such rules confirm that the issue regarding admissibility is one
of adequate notice to the party, not relevance, reliability, necessity, or the quality of
expertise, as set out in the Mohan case. It is therefore presumed the evidence is
admissible, and everything thereafter, by way of challenging the credentials of the expert
or cross-examination on the substance of the evidence goes to weight rather than
admissibility. I believe this over-estimates the probative value of the evidence and
circumscribes the opportunity to undermine and successfully challenge the expert
evidence itself.
43.
Rule 53 does not compel experts to outline their methodology or the reasons for their
conclusions and, of course, there is no provision for the examination of an expert witness
on discovery and, therefore, no right or ability to examine upon the expert report prior to
trial.
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44.
That being the case it is not until the expert has been qualified to give the evidence and in
fact gives such evidence, that the basis for the evidence becomes apparent. By this time
the evidence has been admitted and assumes a degree of credibility to which it may not
be entitled.
45.
Therefore the cross-examination of an expert’s qualifications and the challenging of the
logical underpinnings of the proposed evidence by litigation counsel is of extreme
importance. In my submission the cross-examination of the expert must incorporate not
only the substance of his evidence, but areas which deal with its very admissibility. If
counsel in Ontario were to adopt the approach which exists in many American states, the
courts would at a preliminary stage be confronted with challenges to the proposed
evidence which concerned both its admissibility as well as its credibility.
46.
For example, I recently represented a homeowner who was proceeding against a builder
and its insurer in respect of various construction deficiencies associated with the brick
veneer of his new home. Part of the homeowner’s claim was to have the brick veneer
replaced.
47.
My client called a brick mason to testify as to the quality of the construction of the brick
veneer including its aesthetic appearance.
48.
Conversely the insurer and the builder called a structural engineer to provide evidence
with respect to the suitability of the brick veneer’s construction and its aesthetic
appearance.
49.
I reviewed the engineering report submitted by the builder/insurer and determined it had
no relevance to the proceedings because the engineer had no expertise with respect to the
aesthetic appearance of brick veneer; in addition, brick veneer is not a structural
component and therefore none of the evidence as to the structural integrity of the brick
was necessary; lastly the engineer’s evidence as to the standards by which the veneer
should be judged, being the application of certain CSA Standards, were inapplicable to
the home, however these standards were relied upon by this structural engineer to
complicate or confound the trier of fact.
50.
The cross-examination therefore challenged the relevance and necessity of the engineer’s
evidence, as well as the witness’s reliability. These are all issues that normally are criteria
for admissibility. In my view they can also be used to discredit the witness, even though
the evidence has been admitted.
51.
In the end, none of the evidence of the structural expert was accepted by the trier of fact
in its conclusions on the evidence. The tribunal rejected the evidence as unreliable and
lacking necessity in the sense that the expert could not give better evidence on a matter of
aesthetics than anyone else, so his opinion could be accorded no particular weight.
52.
What this demonstrates is that it may be useful to have the ability to challenge an expert
report using the Mohan criteria, before that evidence is admitted, which would no doubt
save a great deal of time in dealing with this evidence; at the hearing in question, it took
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several days to adduce and cross-examine upon the expert evidence, whereas on a
preliminary motion it may have been ruled inadmissible using the criteria set out by the
Supreme Court of Canada in Mohan.
53.
In my submission there is far too little scope for challenging the admissibility of expert
evidence prior to the trial, which in turn leads to its acceptance and with this acceptance,
comes a degree of credibility which may not be warranted.
54.
It would be far more sensible, if counsel believes that the expert evidence is confusing,
irrelevant or prejudicial, to bring an interlocutory motion prior to trial or at the
commencement of trial to exclude the expert evidence; if it is thereby excluded it could
save a lot of time and expense and prevent the trier of fact from hearing confusing and
prejudicial evidence that might compromise its ability to reach the appropriate result.
55.
If no such action is taken, then in the normal course, such evidence is admitted and it
becomes the function of litigation counsel to deal with this evidence and challenge it in
every way possible, to minimize its damaging influence and perhaps discredit it through
traditional means.
(d)
How to Present the Expert Evidence
56.
Because the current Rules in Ontario do not allow for scrutiny of expert reports prior to
the hearing or trial, experts are allowed to testify once they are qualified; thereafter
certain weight will be attributed to the evidence by the judge or the trier of fact. The
judge or trier of fact then has to decide between the competing expert opinions. To that
end counsel should be aware of certain criteria which may help them in leading their
expert’s evidence.
57.
(i)
When counsel are assisting the expert in preparation of the expert report, he or she
should be aware that all preliminary drafts, working papers and internal communications
between counsel and the expert may be the subject of disclosure to opposing counsel.
58.
In my submission this fact can be of considerable embarrassment to counsel if they have
carried on a written dialogue between themselves and the expert witness prior to the
preparation of the final report, only to have all of this preliminary material produced,
wherein counsel may have persuaded the expert to tailor his evidence to what the counsel
wishes the expert to say!
59.
Rule 31.06(3) of the Rules of Civil Procedure states as follows:
“A party may on an examination for discovery obtain disclosure of the
findings, opinions and conclusions of an expert engaged by or on behalf of
the party being examined that relate to a matter in issue in the action and
of the expert’s name and address, but the party being examined need not
disclose the information or the name and address of the expert where (a)
the findings, opinions and conclusions of the expert relating to any matter
in issue in the action were made or formed in preparation for or in
contemplation of, or pending litigation and for no other purpose; and (b)
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the party being examined undertakes not to call the expert as a witness at
the trial.” (emphasis added)(9)
60.
In accordance with this Rule, if a party intends to call on an expert witness then such
party may be obliged to disclose all “findings, opinions and conclusions” of the expert. It
can be asserted that based on the requirements of this Rule an expert’s draft reports, and
working materials, may be produced to opposing counsel.
61.
In the case of Cheeney v. Peel Memorial Hospital (1990) 73 O.R. 2nd (794)(10) the Court
concluded that the findings and conclusions of experts must be disclosed on discovery
whether they were expressed orally or in writing or whether characterized as preliminary
or final. The Court was of the view that if the “finding” is expressed in a sufficiently
coherent manner such that it can be used by counsel, then it is a “finding” that ought to be
disclosed.
62.
Other cases such as Kelly v. Kelly (1990) 42 C.P.C. 2nd at 181(11) and Naumovich v.
Naumovich (1996) O.J. No.30 (General Division)(12) have followed the view in the
Cheeney case while other cases have declined to do so (see Brown v. Laverey (2002) O.J.
No. 564 O.S.C.J.).(13)
63.
(ii)
Incidental to this enquiry is the notion when faced with the request for the
production of an experts “file”, of whether or not such file is protected by “litigation
privilege”.
64.
While it is acknowledged the litigation privilege recognizes that some communication
between counsel and a third party is immune from disclosure, such litigation privilege
attracts a lot less deference from the Courts than “solicitor and client privilege”.
65.
R.J. Sharp in “Claiming Privilege in the Discovery Process” LSUC Special Lectures
(Toronto 1984) at pages 164-5 has remarked with respect to the distinction between
“solicitor and client” and “litigation privilege” as follows:
“It is crucially important to distinguish litigation privilege from
solicitor/client privilege. There are … at least three important differences
between the two.
First, solicitor/client privilege applies only to
confidential communications between a client and the solicitor. Litigation
privilege on the other hand applies to communications of a nonconfidential nature between the solicitor and third parties and even
includes material of a non-communicative nature.
Secondly, solicitor/client privilege exists any time a client seeks legal
advice from a solicitor whether or not litigation is involved. Litigation
privilege, on the other hand applies only in the context of litigation itself.
Thirdly, and most important is the rationale for solicitor/client privilege is
very different from that which underlines litigation privilege. This
difference merits close attention. The interest which underlies the
protection accorded communication between a client and solicitor from
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disclosure is the interest of all citizens to have a full, ready access to legal
advice.”(14)
66.
Suffice to say that it cannot be determined in advance that by calling an expert witness to
the stand, the extent to which drafts and preliminary documents may be produced. That
being the case, experts may be required to disclose working papers and other draft
materials on cross-examination which could challenge the credibility of the expert
witness once such evidence has been revealed and put to the witness. On the other hand
in the case of General Accident Assurance Company v. Chrusz (1999) 45 O.R. 3rd page
321(15) the Court of Appeal imposed limits on the litigation privilege that could attach to
the expert’s file and protect its exposure. In any event, all good counsel should either ask
for the draft materials prior to trial a request then on cross-examination.
67.
With respect to the presentation of the report and the qualifying of the expert the report
itself should be written in simple language and it should be brief and easily understood by
the Court. It should identify the issue, outline the facts and assumptions and present its
conclusion, clearly and concisely.
68.
Although the facts supporting the opinion must be stated, it is also important to address
material facts that may detract from the opinion so that it will act as fuel for opposing
counsel’s cross-examination.
69.
On qualifying an expert witness a detailed curriculum vitae should be utilized in which
are set out the academic credentials, practical experience, professional positions,
committees and organizations held by the expert, as well as professional recognitions and
honours and lists of publications, giving dates and the names of the publications.
70.
In qualifying the expert, his expertise and reliability should be highlighted and if the
report is submitted then counsel should go through the report carefully with the expert
before the hearing and again when he takes the stand.
(e)
Cross-Examination of the Expert Witness
71.
There are two areas upon which expert witnesses should be challenged, and the theme of
this paper is that, whereas the substance of the expert report is often concentrated upon by
counsel who are cross-examining witness, it is my submission that far more time and
effort should be used in challenging the reliability of that expert testimony. To the extent
that the Court does not perform a gatekeeper function in keeping out questionable
scientific or expert evidence, such function is left to counsel who may not be able to keep
out the evidence, but can destroy it through cross-examination using the criteria for
inadmissibility found in Mahon.
72.
It seems to me that in cross-examination of the expert witness, particularly with respect to
credentials, that this is the area where counsel can prepare cross-examination following
the Mohan tests. The witness can and should be cross-examined as to the (a) relevance of
his evidence, (b) the necessity of the evidence in assisting the Court and (c) the
qualifications of the expert.
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73.
It has been my experience that counsel infrequently cross-examine an expert after he has
been offered for qualification, but rather save their cross-examination until the evidence
in chief is completed.
74.
In my view it is important for counsel to devote at as least as much time to dealing with
the credibility and the credentials of the expert as is spent examining the conclusions in
the expert report.
75.
The reason for challenging at the qualification stage is that it brings into question the
reliability of the evidence at first hand before the evidence has been heard, and raises a
question in the mind that the trier of fact that there may be some problem with the
evidence.
76.
For example, if it can be established on cross-examination that the expertise of the
witness is only tangentially relevant to the issues in the case, then it may be that much of
his or her evidence is discounted before it is even given.
77.
In the example that I gave earlier regarding the masonry veneer, after the expert was
offered as an expert the cross-examination focused on his structural engineering
background and capability and the fact that he had never actually built a masonry wall
himself or taught anybody how to construct a masonry wall; nor had he ever given
evidence with respect of the aesthetics of masonry walls in the past or prepared a report
with respect to the aesthetics of masonry walls in the past. This did much to discount the
credibility of the evidence that was to come, rather than waiting to deal with these issues
at a later stage after the evidence had been adduced.
Conclusions
74.
It is submitted that the preparation of an expert witness for examination in chief and for
cross-examination require great skill and effort on the part of litigation counsel, and the
importance of this effort will affect the outcome of the cases, more and more as experts
continue to dominate the litigation landscape.
75.
Because expert evidence is becoming more predominant in civil litigation cases and
therefore the opinions of experts are more determinative of the final outcome as to the
findings of fact, the function of the counsel with respect to the adducing and challenging
that evidence becomes more crucial.
76.
To that end it seems that counsel in Canada may want to adopt the American approach
found in the Daubert v. Merrell Dow Pharmaceuticals 113 S. Ct. 2786 (1993) case
wherein the reliability of the evidence is challenged at an earlier stage than at trial. In
dealing with the cross-examination of an expert and the challenging of that evidence, the
credentials of the expert and the assumptions used by the expert should be more closely
questioned than has hitherto been the case, so that this evidence is not just admitted
without challenge.
78.
In the last analysis it may be left to counsel to act as the gatekeepers that determine
whether the expert report will or will not be admitted. If the report is admitted then
14
counsel will be the ones to question the weight to be given to it by the rigor of the crossexamination which cross-examination because of the existence of the report, and its ease
of admission, becomes more critical to the final outcome of the litigation. If the report is
not admitted, then counsel have performed a benefit, by shortening the hearing, and
assisting the Court in reaching a conclusion based on appropriate evidence.
BIBLIOGRAPHY
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
R. v. J-L.J. 2000 SCC page 51
Junk Science in the United States and the Commonwealth Yale Journal of International
Law (1996) Vol. 21
R. v. Abbey (1982) 2 S.C.R. p. 24
R. v. A.K. and N.K. (1999) QuickLaw C. 21488 (Ontario Court of Appeal)
Expert Evidence (1991) Wisconsin Law Review at page 1140
R. v. Mohan (1994) 2 S.C.R. page 20
R. V. Melaragni (1992) 73 C.C.C. (3rd)
Rule 53.03(3)
Rule 31.06(3)
Cheeney v. Peel Memorial Hospital (1990) 73 O.R. 2nd (794)
Kelly v. Kelly (1990) 42 C.P.C. 2nd at 181
Naumovich v. Nauvmovich (1996) O.J. No. 30 (General Division)
Brown v. Laverey (2002) O.J. No. 564 O.S.C.J.
Claiming Privilege in the Discovery Process LSUC Special Lectures (Toronto 1984) at
pgs. 164-5
General Accident Assurance Company v. Chrusz (1999) 45 O.R. 3rd page 321
Daubert v Merrell Dow Pharmaceuticals 113 S. Ct. 2786 (1993)
©
Brian M. Campbell
July 2003