Legal development

Recent decision highlights confusion around native title expert evidence

Aerial view of river and bush landscape

    Native Title Year in Review 2022-2023

    What you need to know

    • The court clarified when experts could rely upon other experts – and when the opinions of those other experts are admissible, including when they are not themselves called upon to give evidence. However, the court noted that this did not extend to all expert opinion being admissible when the author is not called.

    What you need to do

    • Consider the implications of this case when briefing experts to prepare reports. It may be the difference between certain evidence being admissible or not.

    Native title expert evidence again in focus for the Federal Court

    As we noted in our Native Title Year in Review 2021-2022 article "Proving connection becomes harder in 2021", expert witnesses is to assist the court in understanding the evidence of the Traditional Owners as well as the anthropological and genealogical data. Expert witnesses are also important generally for providing the court with the inferences that may properly be drawn from that material.

    However, expert evidence still remains subject to the usual rules of evidence under both the common law and the Evidence Act 1995 (Cth). Generally, section 79(1) of the Evidence Act provides that expert evidence is admissible to the extent it is wholly or substantially based on specialised knowledge obtained through a person's training, study or experience.

    Parties regularly contest the admissibility of the evidence of the many experts who are retained by claim group, government parties and other respondents in native title proceedings.

    Western Kangoulu people wished to rely upon various reports

    The Western Kangoulu people claim native title in the area around Emerald in central Queensland. In 2017, the court set the claim down for a trial of separate questions. These questions related to the continued existence of native title and who, if anyone, holds native title rights and interests in the area.

    The applicant had proposed to adduce both oral and written evidence from a number of witnesses – in particular, expert anthropological evidence from Dr Richard Martin.

    The applicant also proposed to adduce additional expert reports that had been prepared in the course of nearby proceedings which, along with the Western Kangoulu, formed a cluster of native title claims known as the Ganggalu cluster. Dr Martin had been involved in the preparation of some, but not all, of these additional reports, and the applicant proposed to call only Dr Martin.

    The State challenged both Dr Martin's evidence and the additional expert material on a number of grounds.

    Court rules in favour of admissibility generally, but not without caveats

    First issue: Whether Dr Martin merely adopted the opinion of others

    The court dismissed the State's objection about whether Dr Martin merely adopted the opinion of others. While it was correct to say that mere adoption and restatement of an opinion does not involve the application of specialised knowledge, that was not the case here.

    Dr Martin had considered the opinions of other qualified persons, both in historical literature and more recent reports, and had made it clear where he had done so. These other expert opinions formed the basis for his own independent opinions about the relevant facts.

    This is normal – experts often refer to, and rely upon, the existing state of knowledge in a field. It would be impractical to require experts to base their opinions only on knowledge or information that has been independently proved.

    To the extent that Dr Martin referred to historical literature as it was presented in the additional expert materials, this was acceptable as a shorthand way of referring to the material in the literature instead of directly citing the original sources.

    Furthermore, as Dr Martin had been a co-author of some of the additional expert material, which represented the joint concurrent opinions of multiple experts, it could not be said that Dr Martin (in relying upon it) was merely relying upon the opinions of others.

    Second issue: Whether the additional material was inadmissible as hearsay or not acceptable basis material

    The court also rejected the contention that Dr Martin could not rely upon the opinions of others where those other opinions would not be admissible under section 79 of the Commonwealth Evidence Act.

    In a circular manner, these opinions were themselves admissible to prove the basis of Dr Martin's opinion (and so were admissible other than as opinion evidence). The weight given to these materials would be a matter for submissions.

    Third issue: Whether hearsay is admissible to show harmony with expert witness's opinion

    The court rejected the applicant's submission, instead holding that some of the expert material was not admissible on the basis that it would show harmony with Dr Martin's opinion.

    Unlike the additional material referred to in the second issue, Dr Martin had not relied upon certain additional reports in reaching his own opinions. Therefore, those reports were relevant only to the extent that the opinions expressed were truly the opinions held by the original author. In other words, they were inadmissible hearsay, since reliance depended upon the truth of the assertion that they were, in fact, the original author's opinion.

    Key insights

    Decision highlights confusion around admissibility of expert opinion – and the material it is based on

    Expert opinion is a well-known area of evidence law that is regular;y used in native title proceedings. However, it has not always been easy to understand whether something is properly admissible or not when multiple experts have been retained over the course of multiple long proceedings. This is particularly the case where those multiple experts seek to rely upon each other in reaching their own opinions.

    Parties should keep in mind the following principles from this case:

    • Expert opinion is not inadmissible merely because it relies upon the expert opinion of others.
    • It is acceptable for experts to refer to previous expert reports that they co-authored to the extent that the final report describes their own opinion.
    • It is also acceptable to refer to previous reports as a shorthand to reference the material discussed in them.
    • Where an expert refers to other material, that other material is admissible.
    • Where an expert does not refer to material, that certain material is not admissible merely to show that the expert's opinion is supported by the material.

    If you wish to have certain material admitted, consider briefing an expert who can consider the material and potentially rely upon it.

    Author: Martin Doyle, Lawyer.

    The information provided is not intended to be a comprehensive review of all developments in the law and practice, or to cover all aspects of those referred to.
    Readers should take legal advice before applying it to specific issues or transactions.


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