Who is an expert?

Admissibility of expert opinion evidence

In order for expert opinion evidence to be admissible in proceedings, as an exception to the general rule against opinion evidence, it should satisfy four tests:

• the expert opinion is to be relevant — relevant evidence is evidence that, if it were to be accepted, could rationally affect (directly or indirectly) the assessment of the probability of the existence of a fact in issue in the proceedings
• the expert opinion is to involve specialised knowledge — the opinion of the expert must be within a field of knowledge that the law recognises as one on which expert evidence can be called
• the witness expressing the opinion is to be qualified —  the witness must be qualified as an expert in the recognised field of knowledge and have acquired specialised knowledge based on the person’s training, study or experience
• the expert opinion is to have a basis —  the opinion of the witness must be wholly or substantially based on the specialised knowledge and the factual basis of the opinion must be disclosed and proven by admissible evidence.

The duties of an expert witness

Rules of Court impose duties on an expert in preparing and giving expert opinion evidence. An expert must comply with :

• the expert witness code of conduct
• court directions in relation to expert witnesses and their evidence
• court directions and requirements for joint conference and report and concurrent evidence.