Evidence

Similar Fact Evidence

In order to show that it would have been possible for an accused to have committed a crime, the Crown may introduce evidence showing that the accused had committed similar offences in the past. This is called similar fact evidence. The problem here, of course, is that a jury may put too much emphasis on previous convictions when coming to a decision.

If a jury, for instance, knows that a man accused of sexual assault has been convicted of such assaults in the past, they may jump to the conclusion that he is guilty of the assault for which he is being tried.

In order to avoid this problem, a judge will often call for a voir dire to decide if a certain piece of evidence should be admitted. A voir dire is really a trial within a trial, but held without the jury present. When the judge has heard both sides and decided whether to allow the evidence (or part of it) or not, the jury is recalled.

Hearsay Evidence

Hearsay evidence is testimony from a witness of what someone else said or wrote about the event at issue. Often hearsay evidence is ruled inadmissible because the person giving it is reporting second-hand information, but there are situations where it is allowed. For instance, deathbed statements are usually admissible.

Opinion Evidence

Evidence that consists merely of a witness's opinion is admitted only if the witness is an expert in the area and the judge and jury members can't be expected to have similar expertise - usually a scientific area such as medicine. The information that expert witnesses give must be relevant and necessary in helping a judge and jury understand something about the case.

Again, the challenge here is to prevent jurors from putting too much emphasis on the testimony of expert witnesses; a specialist's opinion may be well informed, but it is still only opinion evidence not fact.

Character Evidence

The Crown is normally forbidden to introduce character evidence intended to show simply that the accused has a poor character and is therefore likely to have committed the crime in question. The defence may, however, introduce evidence intended to show that the accused has a good character and is therefore unlikely to have committed the crime. This can be a dangerous game for the defence, however, because if "good-character" evidence is introduced by the defence, the Crown is then allowed to enter "bad-character" evidence to counter it.