Choosing and Retaining an Expert

AuthorJohn Hollander
choosing and retaining an expert
chapter two
Choosing and Retaining an
What is an Expert?
   this handbook began with the
statement, “everyone has an opinion.” Often, lawyers
want to lead opinion evidence at trial. ere is a distinc-
tion between opinions that can be expressed by laypeople
and those that require an expert. With this in mind, how
do lawyers determine whether this opinion requires
qualication of an expert witness?
ere are two issues involved in this question. e rst is
the distinction between laypeople and experts. e second
deals with the qualication of experts. In essence, the ques-
tion is, what gives experts their “expertise”?
No Expertise Required
ere are certain subjects upon which everybody can oer
an opinion. To some extent, much of what people say is
based upon opinions, estimates, or in some cases, best
Consider these questions:
. How tall is the building? Maybe twenty storeys.
    
. How fast was the car going? Very fast. I would say
around sixty miles per hour.
. What colour was the baby’s hair? Somewhere between
blonde and ash.
ese answers are all examples of opinions that anyone
can give. People have the ability to form opinions based
upon their everyday experience; they can describe things
that are observable by their senses; they are able to draw
conclusions. Within reason and assuming relevance, these
opinions are all admissible as evidence in court.
Assume that the judge is a “reasonable person.” e
witness is about to express an opinion about something.
Consider the second question above if the judge can
estimate how fast cars go, so can the lay witness. Consider
the third question the judge can describe the colour of
a person’s hair, and the witness is also able to do so. When
trial lawyers ask their witnesses about matters of opin-
ion, there is this distinction to be drawn: is this a matter
that requires an expert’s opinion or can anyone oer one?
What is the training, education, or experience required
to form that opinion? If everyone has it, then the witness
need not be an expert.
According to the Supreme Court of Canada, the test
to qualify as an expert in court is very simple:
The function of the expert witness is to provide for
the jury or other trier of fact an expert’s opinion as
to the signif‌icance of, or the inference which may
be drawn from proved facts in a f‌ield in which the
expert witness possesses special knowledge and ex-
perience going beyond that of the trier of fact. The
choosing and retaining an expert
expert witness is permitted to give such opinions for
the assistance of the jury. Where the question is one
which falls within the knowledge and experience of
the triers of fact, there is no need for expert evidence
and an opinion will not be received.1
In the second question above, a forensic engineer
with a stopwatch can estimate the speed of a car. e
facts recited in testimony might be these:
• e car reached the starting point.
• e witness started the stopwatch.
• e car drove to the nishing point.
• e witness stopped the stopwatch.
• e witness measured the distance.
Distance divided by time equals speed.
• With simple arithmetic, the answer is obvious.
Does that information require an expert? Could anybody
familiar with a stopwatch be able to provide similar testi-
mony? is depends upon how accurate the measurement
must be the circumstances may require very accurate
information; it may require multiple tests. e point is
that the basic information is available to almost anybody,
but the greater accuracy required, the greater reliability,
the more likely it is that the evidence of an expert witness
will be preferred to that of a layperson. at is a function
of relative credibility, and not admissibility.
Virtually everybody uses computer software. is in-
cludes a suite of programs that includes word processing
1 R v Béland, 1987 CanLII 27 at para 16 (SCC) [Béland].

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