Expert Evidence - Interesting Cases

An experts evidence is not inadmissable merely because the expert has not acknowledged or has breached the code but “where an expert commits a sufficiently grave breach of the code, a court may be justified in exercising its discretion to exclude the evidence under s135 or s137 of the Evidence Act.

various areas of expertise identified over numerous topics;

multiple expert conferences ordered.

the [expert evidence] was not admissible to … [as it] was not “wholly or substantially based on” “specialised knowledge based on [the experts] training, study or experience”.

Evidence Act 1995 (NSW) s79(1)

As a general rule, trial judges confronted with an objection to admissibility of evidence should rule upon that objection as soon as possible.

Often the ruling can and should be given immediately after the objection has been made and argued.

If, for some pressing reason, that cannot be done, the ruling should ordinarily be given before the party who tenders the disputed evidence closes its case.

That party will then know whether it must try to mend its hand, and opposite parties will know the evidence they must answer.

Under the rules of evidence the primary judge was permitted to take account of matters not proved in evidence in this case only if they were matters of which judicial notice could be taken.

It was not suggested that the causes of silicosis were matters for judicial notice.

Please note that this case relates to specific requirements of the Dust Diseases Tribunal Act 1989 but is nonetheless interesting.

Lack of independence goes to weight.

Receipt of inadmissable material

Lack of independence is not of itself sufficient to establish inadmissablity

In short, if evidence tendered as expert opinion evidence is to be admissible, it must be agreed or demonstrated that there is a field of “specialised knowledge”;

there must be an identified aspect of that field in which the witness demonstrates that by reason of specified training, study or experience, the witness has become an expert;

the opinion proffered must be “wholly or substantially based on the witness's expert knowledge”;

so far as the opinion is based on facts “observed” by the expert, they must be identified and admissibly proved by the expert, and

so far as the opinion is based on “assumed” or “accepted” facts, they must be identified and proved in some other way;

it must be established that the facts on which the opinion is based form a proper foundation for it;

and the opinion of an expert requires demonstration or examination of the scientific or other intellectual basis of the conclusions reached:

that is, the expert's evidence must explain how the field of “specialised knowledge” in which the witness is expert by reason of “training, study or experience”, and

on which the opinion is “wholly or substantially based”, applies to the facts assumed or observed so as to produce the opinion propounded.

If all these matters are not made explicit, it is not possible to be sure whether the opinion is based wholly or substantially on the expert's specialised knowledge.

If the court cannot be sure of that, the evidence is strictly speaking not admissible, and, so far as it is admissible, of diminished weight.

And an attempt to make the basis of the opinion explicit may reveal that it is not based on specialised expert knowledge, but, to use Gleeson CJ's characterisation of the evidence in HG v R [1999] HCA 2; (1999) 197 CLR 414, on “a combination of speculation, inference, personal and second-hand views as to the credibility of the complainant, and a process of reasoning which went well beyond the field of expertise” (at [41]).

While it may readily be accepted that a party is ordinarily entitled to discovery and inspection of all discoverable documents in the possession or control of the opposite party (save those for which a valid claim for privilege from production is claimed) it is important to bear steadily in mind that discovery is but a tool to be used in the pursuit of justice and that the right to discovery and inspection is not without its limits. The first and most obvious limit is that a party does not have a right to inspect documents that are discovered if there is a valid claim to privilege from production (as eg on the grounds of legal professional privilege). Secondly, because the law recognises that the assertion of compulsive power requiring production must be balanced against the needs of justice, a party inspecting the documents of the opposite party may not use them except for the purposes of the action in which discovery is made.

Where it is said that the documents are confidential, it may be accepted that the fact that the documents are confidential will not ordinarily be a sufficient reason to deny inspection by the opposite party. In most cases, the fact that the documents may not be used except for the purposes of the litigation concerned will be sufficient protection to the party producing them. But where, as here, the party obtaining discovery is a trade rival of the person whose secrets it is proposed should be revealed by discovery and inspection, other considerations arise.

Once the documents are inspected by the principals of the trade rival the information which is revealed is known to the trade rival and cannot be forgotten. Confidentiality is destroyed once and for all (at least so far as the particular trade rival is concerned). To say that the trade rival is bound not to use the documents except for the purposes of the action concerned is, in a case such as this, to impose upon that trade rival an obligation that is impossible of performance by him and impossible of enforcement by the party whose secrets have been revealed. How is the trade rival to forget what internal rate of return the competitor seeks to achieve on a new investment of the kind in question? How is the party whose hurdle rate has been revealed to know whether the rival has used the information in framing a tender? Thus, if the trade rival may inspect the documents concerned, the confidentiality of the information in them is at once destroyed. Is that necessary for the attainment of justice in the particular case?

s55 Relevant evidence

s76 The opinion rule

s79 Exception: opinions based on specialised knowledge

s135 General discretion to exclude evidence

s136 General discretion to limit use of evidence

Order 44

Forms 44 and 44A