By Luke Buchanan
Co-Founder & Principal, Buchanan Rees Dispute Lawyers | Best Lawyers Australia, Litigation & Class Action Litigation
In your experience, what are the most common mistakes lawyers make when instructing experts to prepare evidence on the quantum of damages?
The question really comes back to a mistake which lawyers commonly make when instructing experts more generally. In order to be admissible, it is critical that an expert report exposes the reasoning of the expert which underpins the opinions expressed in the report. In instructing and working with an expert, it is important for the lawyer to make sure the expert understands and complies with that requirement. In particular, it is not sufficient for the expert simply to state their opinions and assume that their qualifications and experience alone will be sufficient to give weight to those opinions.
How have recent court decisions shaped the standard of admissibility and persuasiveness for expert evidence in commercial litigation and class actions?
A high profile recent decision in which the court ruled on the admissibility of a report prepared by a forensic lipreading expert is Lehrmann v Network Ten Pty Ltd (Expert Evidence) (No 2) [2023] FCA 1647.
Lee J held that “…the admissibility of expert evidence does not depend upon establishing a level of absolute precision in an area of specialised knowledge, and it would be erroneous to adopt a counsel of perfection. One must take areas of specialised knowledge as one finds them. The weight and eventual probative value of the evidence, or parts of the evidence, is quite another thing.”
The counterfactual is often the heart of damages assessments. How can lawyers work effectively with experts to construct a robust and defensible counterfactual scenario?
An expert report does not exist in isolation from the lay evidence in the proceedings. Rather, expert evidence will often intersect with, and need to refer to, the lay evidence. For example, it is frequently the position that assumptions given to the expert need to be proved by way of evidence from lay witnesses.
Counterfactuals are a good example. If a plaintiff says that, had it not been for the defendant’s breach of duty, the plaintiff would have done (or not done) a certain thing, the plaintiff needs to prove that by way of affidavit evidence. The expert can then be given an assumption which is consistent with that evidence.
Of course, this emphasises the importance of ensuring that the lay evidence is also admissible and persuasive because if that evidence is not accepted by the Court, the assumption(s) provided to the expert (and consequently, the expert report itself) may be seriously undermined.
From a litigator’s perspective, what strategies do you recommend to ensure expert evidence is not only technically sound but also compelling to judges or arbitrators?
To a large extent, this comes back to the basics; namely, establishing that the expert has the relevant expertise (based on their qualifications and experience), complying with the abovementioned requirement to expose the reasoning of the expert and complying more generally with the Expert Witness Code of Conduct or its equivalent (in the various state Supreme Courts) or the Expert Evidence Practice Note (in the Federal Court).
Further, one should not underestimate the advantages which come from instructing an expert who is not only technically sound but who can also write well for a judge. The best experts are those who understand that the primary purpose of the report is not explanatory but rather, evidentiary; that is, not to teach a group of non-experts (i.e., judges and lawyers) about a bunch of concepts in the relevant field but rather, to state the expert’s opinions on issues relevant to the proceedings and to prove, on the balance of probabilities, the correctness of those opinions.
Looking ahead, how do you see the role of expert evidence in proving damages evolving, particularly with the rise of complex financial modelling and economic analysis in litigation?
The “basics” referred to above are well-established and are unlikely to change. However, the more complex the subject matter, the fewer the number of people who will have the requisite qualifications and experience to prepare an independent expert report for use in litigation. “Dabbling” in the relevant field is not enough. Hence why my co-presenter on 18 September (Dr Luke Wainscoat of HoustonKemp) is a good person to know!
If you would like to hear more from Luke Buchanan, please register for our upcoming seminar, where he will present: Using Expert Evidence to Prove the Quantum of Damages
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