Introduction

• Author: David M. Paciocco/Lee Stuesser
• Pages: 1-23

1. THE ROLE OF THE LAW OF EVIDENCE

Two kinds of issues get adjudicated in most hearings, issues of law and

issues of fact. In the overwhelming majority of cases, the same adjudi-

cator decides both kinds of questions, but in jury trials responsibility

is divided; judges are the “triers of law” and the juries are the “triers of

fact.” Whether the trier of fact is a jury, or a judge, or an adjudicator or

a panel of adjudicators in an administrative hearing, it is obvious that

the function of the “trier of fact” is critical to achieving a just outcome.

The goal of any adjudicative hearing is to resolve the relevant contro-

versy according to law, but typically the facts are in dispute and need

to be resolved correctly before the substantive law can be applied cor-

rectly. In Canada, the model for resolving factual controversies is

adversarial. The parties produce the information or “evidence” that the

trier of fact will use to make its decision. Evidence, therefore, is the

data that triers of fact use in performing the fact-finding function, and

it is the role of the law of evidence to regulate what data triers of fact

will receive.

It is apparent, then, that the “rules of evidence” do not exist for their

own purpose. Instead they exist to permit facts to be resolved properly

so that the rules of substantive law can be applied. Given this, it is help-

ful to define “evidence” according to its function: evidence of a fact is

information that tends to prove it. This definition reinforces that the

rules of evidence are mainly facilitative, secondary, or “adjectival,” in the

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INTRODUCTION

chapter 1

sense that they are meant to assist in the correct application of other

rules of law. As a matter of principle, the rules of evidence should accom-

modate the presentation and consideration of any information that could

help the trier of fact to come to an accurate factual determination.

The animating principle that captures this sentiment is sometimes

called the “principle of access to evidence,” and it has indeed been

influential in the development of the rules. Yet the laws of evidence do

not just facilitate findings of fact. They often exist to accomplish

important policy objectives or to pursue principles of their own. For

example, the rule preventing the tribunal from considering some

unconstitutionally obtained evidence exists to ensure that the trial

process is fair and that the administration of justice remains unsullied

by police misconduct. Denying such evidence to the trier of fact can

impede accurate fact finding because the excluded evidence may be rel-

evant and probative of the facts in issue. Yet the evidence is rejected

because competing considerations are given priority over the value in

coming to a correct disposition of the matter in controversy.

The development of the law of evidence has been the product of

the continuous balancing of competing considerations. Its rules can be

understood only by paying close regard to the interests at stake. These

rules perform a variety of functions, controlling what information the

trier of fact can receive, how that information is to be presented, as well

as the use that can be made of it.

2. ADMISSIBILITY AND EXCLUSION

2.1) Generally

Most rules of evidence deal with the admissibility of evidence. Evi-

dence is “admissible” when it can properly be considered by the trier

of fact. It is “excluded” when it cannot. This exclusionary function is a

distinguishing characteristic of the common law rules of evidence.1

Most rules of evidence identify information that cannot be admitted.

Information is excluded for a variety of reasons. Occasionally, as

with unconstitutionally obtained evidence, it is because of competing

considerations of policy or principle. Sometimes evidence is excluded

because of practical considerations relating to the efficiency of the trial

process. For example, the collateral facts rule prevents a party from

2The law of Evidence

1 J.B. Thayer, A Preliminary Treatise on Evidence at the Common Law, reprint of

1898 ed. (New York: Augustus M. Kelly, 1969) at 264.