25 Admissibility of expert opinion evidence


An opinion by an expert that is part of expert evidence offered in a proceeding is admissible if the fact-finder is likely to obtain substantial help from the opinion in understanding other evidence in the proceeding or in ascertaining any fact that is of consequence to the determination of the proceeding.


An opinion by an expert is not inadmissible simply because it is about—


an ultimate issue to be determined in a proceeding; or


a matter of common knowledge.


If an opinion by an expert is based on a fact that is outside the general body of knowledge that makes up the expertise of the expert, the opinion may be relied on by the fact-finder only if that fact is or will be proved or judicially noticed in the proceeding.


If expert evidence about the sanity of a person is based in whole or in part on a statement that the person made to the expert about the person’s state of mind, then—


the statement of the person is admissible to establish the facts on which the expert’s opinion is based; and


neither the hearsay rule nor the previous consistent statements rule applies to evidence of the statement made by the person.


Subsection (3) is subject to subsection (4).