Evidence About Credibility and Reliability

• Author: David M. Paciocco/Lee Stuesser/Palma Paciocco
• Pages: 592-623

592

CHAPTER 10

EVIDENCE ABOUT

CREDIBILITY AND

RELIABILITY

1. CREDIBILITY AND RELIABILITY

E VA LU AT ION

Simply because evidence has been admitted does not mean it will be

used. The entire enterprise of admitting evidence is undertaken to fur-

nish the trier-of-fact with the data for decision making. Once evidence

is admitted, the trier of fact must decide what to make of it.

A critical determination in discharging this obligation is for the

trier of fact to decide what admitted information it will accept and act

upon. There is no presumption that witnesses are credible or that their

testimony is accurate,1 or that evidence that has been admitted will be

accepted and utilized. This is true even of evidence that has gained

admission pursuant to a n admissibility rule that includes a preli minary

reliability assessment, such as hearsay evidence admitted under the

principled exception.2 The trier of fact is free to accept some, all, or

none of the admissible evidence offered by a witness.3

In deciding what weight to give testimony, triers of fact should

evaluate that evidence at the end of the case in the context of all other

evidence. When deciding whether to accept testimony as accurate,

triers of fact wil l consider both “credibility” (the honesty of the witne ss

1 R v Thain (2009), 243 CCC (3d) 230 (Ont CA) at para 32.

2 See the dis cussion in Chapter 4, Section 2.2, “Thre shold Reliability.”

3 R v RR, 2017 ONCA 141 at para 7.

Evidence About Cred ibility and Reliabilit y593

when relating the testimony) and “reliability” (the accuracy of the testi-

mony given by an honest witness).4 They will do so by considering a

range of things, including the character of the witness; the demeanour

of the witness; the condition and capabilities of witness (i.e., things

that may affect their opportunity or capacity to observe); the plausibil-

ity of the testimony (as measured through “the probabilities that sur-

round the currently existing conditions”);5 the internal and external

consistency of the witness’s evidence; and whether there is supporting

information (in other words, how the testimony “stacks up” to other

available information).6

Much of the data that will be used in examining credibility and

reliability is derived from primarily material evidence — information

that is called to prove or disprove a substantive issue in the case. For

example, a witness’s description of a suspect may not be consistent

with other, more reliable evidence about that suspect, and so the wit-

ness’s description will be discounted or rejected. Or, two independent

witnesses may support each other by offering similar testimony. Other

data will come from secondarily material evidence that is admitted for

the sole purpose of assisting the trier of fact in assessing other evi-

dence. For example, a police officer who purports to remember that

the accused smelled of alcohol when arrested for impaired operation a

year before may be asked whether they made a note of thi s observation

at the time, and, if not, how many other impaired operation cases they

have processed in the past year. The answers to these questions are not

primarily material evidence, but they may assist in evaluating the reli-

ability of the police officer’s claim that the accused smelled of alcohol.

Or, a police officer may be asked whether they have been disciplined

before for providing misleading testimony. An affirmative answer has

nothing to do with the primarily material issues in the case but may

assist in evaluating the credibility of the officer.

The range of information that may conceivably assist in credibility

and reliability evaluat ion is exceedingly broad, since lea rning anything

about the quality of the witne ss’s memory, attentiveness, experience, or

honesty can help. Yet courts are practical institutions. Time and resour-

ces are not unlimited, and such w ide-ranging inquir ies would be apt to

add little, at great cost. With the exception of the controlled but gener-

ous approach taken to cross-examination, the law is therefore guarded

about the admissibility of secondarily material evidence.

4 See the disc ussion in Chapter 2, Section 4.1, “How Believable I s the Evidence?”

5 Faryna v Chorny, [1952] 2 DLR 354 (BC CA) at 356 [Faryna].

6 R v S(DD), 2006 NSCA 34 at para 77.

THE LAW OF EVIDENCE594

This chapter describ es the rules that control the presentation of sec-

ondarily material evidence, including the special procedures that may

apply. Most of the rules discussed here apply to the cross-examination

of witnesses c alled by opposing counsel. The special rules th at apply to

evidence about the credibility of a party’s own witnesse s are addressed

in Chapter 11, “Secondary Materiality and Your Own Witness.”

2. WITNESS DEMEANOUR

The term “demeanour” is often used, but there is no generally accepted

definition of it. Typically, the term is used in the law of evidence to

describe the comportment of a witness while testifying insofar as it

betrays aspects of the witness’s attitude, knowledge, or emotional state

relevant to their credibility or reliability. However, as some of the deci-

sions about to be discussed reve al, the term “demeanour” is sometimes

used to apply to in-court observat ions made by the trier of fact about the

physical appearance or comportment of someone linked to the event,

who is not necessarily acting as a witness at the time the observation

is made, even to support primarily material inferences in the case. For

example, the accused may make a threatening gesture in court that

can support the “after-the-fact conduct” inference that the accused is

attempting to hide their complicity by intimidating the witness.7 We

will therefore use the term in its broader meaning, to encompass any

observation made in court by the trier of fact of a witness’s or a party’s

physical appearance or comportment th at the trier of fact relies upon to

draw inferences in the c ase. Given the theme of the current chapter, the

emphasis in the following discussion will be on demeanour evidence

used in evaluating the credibility or reliability of witnesses.

Demeanour is not evidence, per se, as it has not been admitted at

the proceeding. It has inste ad been observed directly by the trier of fact.

Subject to limits, the trier of fact is nonetheless entitled to use those

observations when assessing that witness’s testimony.8 For example, if

a witness is co-operative with one side and hostile to another, this may

denote partiality.

However, care should be taken. “It is now acknowledged that

demeanour is of limited value because it can be affected by many fac-

tors including the culture of the witness, stereotypical attitudes, and

7 See Chapter 2, S ection 3.6, “After-the-Fact Conduct.”

8 R v S(N), [2012] 3 SCR 726.