5 Things to Consider When Working with Expert Evidence

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David Talintyre is a barrister at Level 22 Chambers. He has over 20 years of experience at the bar taking on diverse commercial, construction, engineering, mining, insurance, equity, and personal injury disputes. He is also an accredited and practicing Mediator and Commercial Arbitrator, with a special interest in Alternate Dispute Resolution.
David has worked with expert witnesses on numerous matters. Below, he summarises some key pieces of advice and pitfalls to avoid when engaging an expert and overseeing the report writing process.
Expert evidence is a feature of most forms of litigation and it can be critical to the outcome of the case. Such evidence can be difficult to source and is almost always both time consuming and expensive to prepare.
What makes it all the more remarkable is that aside from some basic instruction in relevant evidentiary principles, lawyers often receive very little training in how best to ensure that compelling (or at least adequate) expert evidence is available to be deployed in any settlement negotiations and, if necessary, adduced at trial.
Of course, most expert witnesses do not receive even a rudimentary education in how to effectively deliver the product they are selling – the application and communication of their particular expertise to the relevant facts. Some get better with repetition and experience – this is called learning the hard way. Others get put in the round file of “never to be engaged again”, which is a little tough, given their perceived failures are often not their fault.
What follows then is intended as practical guidance, both for those whose job it is to engage and work with expert witnesses, and for their intended victims – the experts themselves. If each have a better idea of what is endeavouring to be achieved by such evidence, we may just see the quality of it improve, to the benefit of all stakeholders in litigation processes.

1. What was the question again?

It is vital to understand what the real issues in dispute are, and which of those issues actually require expert evidence. It is never simply a matter of plumping for a likely expert discipline and sending the hapless candidate the pleadings and some factual material, blindly hoping they will figure out what the parties may end up fighting about at any mediation or trial.

Early advice from the preferred trial counsel can be valuable here, since they are generally more attuned to forensic requirements (i.e. what works to prove cases). They can assist to distil the issues, isolate those that call for an expert opinion to best determine them and give advice as to precisely what kind of expert evidence is required.

One simple trick for new players though is to consider any allegations in the pleadings that include adjectives (e.g. ‘adequate’, ‘reasonable’, ‘effective’, ‘proper’) as potential issues for opinion evidence. For example, expert evidence as to the application of any specialised industry standards, codes or guidelines – or an opinion as to common industry or professional practice – can be relevant to the Court’s assessment of such adjectival issues.

Causation is another issue that may require expert opinion to assist the parties and the Court to understand why something has occurred (e.g. a technical failure, a natural process, how a human interaction resulted in an accident or other misadventure).

2. Academic or hands-on operator?

Once you have understood the real issues in dispute, it is then important to get the right expert for the issue. Although many rush to find a professorial boffin with many post-nominals, it need not be an academically qualified expert. Sufficient experience in a relevant practical field can also qualify an expert. Specialised knowledge is the test, which can be gained by significant experience, not only by training or tertiary qualifications.

For example, a case concerning scaffolding might call for the opinion of a structural engineer or that of a highly experienced scaffolder…or both. It depends on what the issue to be determined requires by way of opinion evidence. The latter may require some help in the expression of their opinions but then again many engineers occasionally struggle with the English language!

Although they can be a good first stop, be prepared to look further afield than any candidates that expert ‘brokers’ may offer. You may need to go interstate or overseas to find the best fit for the issue under consideration. I once located an excellent truck rollover expert in New Zealand whose opinion was eventually preferred by the Court of Appeal over that of a local.

Ensure the basis of the relevant expertise is disclosed in the expert’s CV and it also helps to have the expert include something specific to the relevant issues as to their expertise in the body of their report. This gives the reader comfort that the expert has the authority to hold forth on the issues they are charged with opining upon, and may forestall cross-examination as to expertise.

Engaging the right expert witness can be a time-consuming task, especially in cases where you require an expert with a very niche area of expertise, or where you are not even sure as to what area of expertise is required for the matter. In those instances, an expert witness sourcing service can be of great assistance.

3. Ensure the expert is provided with the tools to do the job properly

Brief the expert with a summary of relevant facts and targeted documents, with particular guidance to relevant subpoenaed or discovered material. Consider providing a chronology and/or index. Make it user friendly.

Do not simply dump some telephone books of paper into their lap and leave it up to them to locate all relevant facts. The more diligent amongst them might extract the relevant factual considerations from the material but your client will pay for the time they spend doing so and even then, they usually miss something critical. The lazy ones simply do not bother and you end up commissioning supplementary reports to get them to deal with the material they have missed, which is never as compelling as a comprehensive primary report.

However, be careful about being overly prescriptive too early in the process by pretending to identify all factual assumptions for them in an initial letter of instruction. You are not the expert in the respective field after all and you may not correctly identify all necessary factual assumptions to ground any required opinion.

To reach a landing on what factual material is required, and the precise factual assumptions the expert will need to make, it is best to confer with the expert after they have read what has initially been provided before they write even the first draft of their report. Early opinions based on less than complete material or a misunderstanding of the issues or facts can be hard to shake, so best to get to them before they put pen to paper.

Ensure the expert understands the issues they are being asked to assist the Court with determining and that they have actually read and understood the existing factual material. Kick it around with them a little. Ask the dumb questions. Go down a few rabbit holes and see what is in them. Occasionally, the case can turn upon something unexpected as a result of such general discussion. Find out if they need anything else before they commence drafting their report.

This initial conference process can save costs if the expert indicates an unfavourable preliminary view, although check that this has not proceeded from an incomplete understanding of the factual matrix. It may also become apparent that the expert does not possess the required expertise to provide an authoritative opinion on the issue. Better to find this out at an early stage than after they have written an expensive report.

Only after conferring with the expert and providing any further factual material required and perhaps conferring again should you finalise the questions you wish the expert to answer. Lawyers do not always ask the correct questions at the outset because they lack the expert’s specialised knowledge to understand what they should consist of.

When framing the questions for the expert, avoid ultimate issues or legal questions that are strictly matters for the Court. For example, the expert should be asked to consider precautions reasonably available to a defendant rather than opine on whether the defendant was ‘negligent’ in not taking any number of them.

4. Do not allow the expert to play fact finder

When expert witnesses are asked to give an opinion, they frequently make the mistake of pretending to be the investigator and arbiter of the underlying facts, often to suit their particular pet theory. They will rat through the material and start drawing factual conclusions, as if they are the judge charged with doing so.

This is the instructing lawyers’ fault if it is allowed to go unchecked. Firstly, by not providing the expert with the factual assumptions the expert is expected to adopt in arriving at their opinion. Secondly, by not instructing the expert to provide alternative opinions if different factual findings on various issues are possible on the currently known evidence.

If you do not drive what the expert is given, asked to assume, and required to consider, you will get the substandard expert evidence you deserve, replete with clunky factual logic and susceptible to being rejected by the Court if other factual findings are made.

This underlines the basic point that the preparation of good expert evidence is often an iterative process of briefing, questioning and discussion before any report is written. Assist the expert to get at the necessary facts, rather than leaving the expert to figure them out on their own.

5. Will the expert evidence do the job?

Consider whether you need any other experts in other fields or whether a joint approach is necessary because the issue is complex and overlaps more than one field of expertise. This is often a better approach than tempting the initial expert to stray outside their particular scope of specialised knowledge simply to obtain a ‘one stop shop’ kind of report. Such ‘experts on everything’ are usually found out in cross-examination and are not very persuasive, with the worst ones suffering reputational issues as a result.

Ensure your expert understands the need to identify the factual assumptions or physical observations they have relied upon and distinguish them from the opinions given. Ideally, these should be stated simply and separately in the report, without editorial comment from the expert. They can then be referred to again when the expert provides the reasons for their opinion(s).

Ensure you can prove at the very least in a prima facie manner the factual assumptions relied upon by the expert and consider getting opinions based on alternate or even competing factual scenarios if there is likely to be a dispute over any of the assumptions relied upon.

Ensure your expert understands the need to state reasons for the opinion given, including how the opinion is drawn from their expertise. Bald conclusions are often inadmissible, rendering the evidence nugatory.

Giving reasons means explaining how the expert’s specialised knowledge applies to the facts assumed or observed to produce the opinion given. Many experts do not understand this or make the mistake of considering something to be so obvious (often as a result of their deep subject knowledge) that it does not require explanation. Prod them to do so until any lay person can understand the basis for the opinion given.

Some experts are not particularly good at expressing their opinions in writing. They may have all the required knowledge to give a good answer but cannot communicate it effectively. Assist them to settle their report, so their opinions are communicated clearly (and number the paragraphs!) but be careful never to suggest what their opinion is or should be. Open ended questions designed to clarify rather than predict are critical in such a process. Some expert sourcing services provide a barrister-led proofing or quality assurance process intended to ensure the professional standard and admissibility of the expert report.

Some lawyers and clients get nervous about settling expert reports, wrongly believing that it is somehow improper. On the contrary, it is an error not to do so if the initial draft will not assist the Court. As McDougall J said in Thiess P/L v Dobbins Contracting P/L [2016] NSWSC 265 (emphasis added):

“Lawyers must play an active, and important, part in the preparation of statements of expert evidence. First of all, the lawyers for a party who proposes to rely on expert evidence must inform the expert of the assumed facts on which his or her opinion is to be based. To enable the opinion to have any value, the statement of assumed facts (and of course, those facts include documents) must be comprehensive.

Next, the lawyers should do what they can to ensure that the expert expresses his or her opinions in a way that demonstrates clearly the application of specialised knowledge to those assumed facts and the reasoning process that leads to the opinions expressed. Of course, it is a matter for the expert, and only the expert, to formulate those opinions, and to employ an appropriate reasoning process in doing so. However, if the expert’s statement of evidence is to be of any real utility, the lawyers who have retained the expert must do what they can to ensure that the reasoning process is adequately displayed. In this case, the lawyers for both the plaintiffs and Mr Bate appeared to be either ignorant of, or uncaring as to, their responsibilities in this regard.” [21]-[22]

His Honour probably had to slog through more unintelligible expert evidence than most of us will face in a career, so I hope his exhortations encourage those practitioners who may have previously felt it improper to interfere with the manner in which the expert they have retained chooses to express their opinion. If you do not thoroughly understand it, how do you expect the other side or the judge to?

Make sure your expert is staying within their field of expertise. The reasoning process required of them is a good litmus test for this. If the opinion does not identifiably proceed from their field of specialised knowledge, they have strayed beyond it and the opinion should be omitted from their evidence.

Always provide your expert with any competing expert and/or factual evidence for consideration and at least discuss it with them to ascertain their views, even if no reply/supplementary report is commissioned.

Discuss the expert’s opinion(s) with any factual witnesses and ensure there is no practical fact or circumstance which might invalidate the opinion if it comes out in evidence (assume it will).

Prepare your expert for participation in the conclave process and the production of a joint report. Get a facilitator and/or scribe to assist if necessary. Warn them not to feel bullied by a more experienced or aggressive opposing expert unless they are genuinely persuaded their opinion requires modification.

Prepare your expert for giving oral evidence; in particular, how to conduct themselves when being cross-examined and/or giving concurrent evidence. This is a whole other topic the details of which are beyond the scope of this paper but never neglect witness preparation, even if the expert is an experienced court room performer.

And, finally, debrief the expert after the trial and offer feedback as to their performance in the witness box. If their opinion was rejected by the Court, make sure they understand why. A review of weaknesses or faults in expert evidence is likely to be helpful for the lawyers as well as experts, who can improve the standard of their evidence the more matters they work on.

Your search for a winning expert stops here.