Materiality, Relevance, and Admissibility of Evidence

In determining the admissibility of evidence, the judge should determine the relevance and materiality of the information.Evidence must be both relevant and material to be admitted. In the United States, a judge presiding over a jury trial will determine the relevance and the jury will determine the materiality. In a bench trial, the judge presides as both trier of law and trier of fact. Therefore, he will determine both the relevance and the materiality of the evidence presented.

Materiality

Evidence is material if it is offered to prove or disprove a specific fact in issue. Thus, evidence is material if it relates to one of the particular elements necessary for proving or disproving a case. If evidence is not material, it the defense or prosecution may object to the use of the evidence on grounds that it would mislead the trier of fact, result in inefficient trials, and prove a distraction to the substantive issues. The exclusion of immaterial evidence is sometimes called the collateral facts rule.

Some evidence may be admissible even if it does not bear directly on an issue of fact as long as it has a relationship to the weight or credibility of evidence. Thus, when a witness testifies their credibility, perception, memory and narration or communication are all material even though they are not directly related to an issue of fact.

Relevance

Evidence is relevant if it indicates a relationship between facts that increases the probability of the existence of the other. A trier of fact (judge or jury) determines the sufficiency or weight of the given evidence. In order for evidence to meet the relevance threshold, there must be merely some probative value.

Prejudicial Value

Although relevant and material, evidence MAY be excluded if its probative value is substantially outweighed by the danger of unfair prejudice, confusion of the issues, or misleading the jury, or by considerations of undue delay, waste of time, or needless presentation of cumulative evidence.

Example: Photos of the murder victim are generally NOT relevant in the United States to prove death because their prejudicial value outweighs the probative value. However, photos may be relevant to any other issue, such as method of killing, defendant's claim of self-defense, etc.

Conditional Relevance

In many cases, a given piece of evidence will only be relevant if another fact is established. This is called conditional relevance. In the United States Federal system, conditional relevance is governed by Federal Rule of Evidence 104(b):

When the relevancy of evidence depends upon the fulfillment of a condition of fact, the court shall admit it upon, or subject to, the introduction of evidence sufficient to support a finding of the fulfillment of the condition.

In practice conditional relevance tends to apply in the following cases:

1. Foundation for admissibility of physical evidence or expert opinions
2. Proving personal knowledge for witnesses
3. Proof of defendant's prior bad act

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See Evidence