When Expert Evidence Goes Wrong – The 5 Common Mistakes – Part 2

In complex litigation, counsel will often need expert assistance before the issues have been fully formulated. The expert may be asked to explain how a market operates, how a transaction should be understood, which documents are technically significant or whether a particular interpretation is commercially plausible. This early involvement can be extremely valuable, but risk arises when the expert moves beyond explaining the subject matter and begins shaping the case they will later be asked to assess independently.

 

How the problem can arise

Counsel may initially instruct an expert because the case involves unfamiliar technical issues. The expert will be expected to explain the relevant market practice, identify the important features of the case and help the legal team understand the significance of the available evidence. During those discussions, the expert may also express preliminary views about what happened, why it happened and how particular conduct should be interpreted.

Although those views may be tentative and based on incomplete information, they can nevertheless become accepted by the legal team because they provide a coherent explanation of a difficult case. The expert’s analysis may then influence the way witness statements are prepared, disclosure is reviewed, questions are put to factual witnesses, and the case is pleaded.

By the time the expert is formally asked to provide an independent opinion, the expert’s own earlier views may already form part of the case they are being asked to support.

 

The expert as educator

There is nothing improper about an expert educating counsel and in many cases, this is essential. A legal team may need to understand specialist terminology, commercial conventions, pricing mechanisms, accounting treatment, trading structures or regulatory requirements before it can identify the relevant legal and factual issues. The expert may also help counsel distinguish between matters that are technically important and those that are not.

The difficulty lies in maintaining the distinction between explaining the subject matter and determining the client’s case theory.

An expert can properly explain that certain conduct is consistent with a particular market practice. It is a different matter to assert, before all the evidence has been considered, that the conduct proves a specific intention or establishes a disputed factual conclusion.

Preliminary technical assistance can therefore become problematic if tentative views are treated as settled opinions.

 

When preliminary views become pleaded facts

Once an expert’s interpretation has been accepted by the legal team, it can become embedded in the case. The wording may find its way into pleadings, witness statements, correspondence and submissions, which can lead to a technical interpretation that may become presented as an established fact. If the expert is then asked to produce a report addressing the pleaded case, it may support a proposition that originated with that expert, creating a circular process.

The expert explains the case to counsel, counsel incorporates the explanation into the pleadings, and the expert is then asked whether the pleaded explanation is correct.

 

The risk of confirmation

The more time spent explaining and refining the theory, the harder it may be to reconsider it objectively and new evidence may be interpreted through the framework already established. Documents supporting the theory may appear especially significant, while documents pointing in another direction may be treated as exceptions or misunderstandings. The expert may also feel an understandable reluctance to undermine a pleading or witness statement that was prepared in reliance on their earlier advice.

Once a coherent explanation has been formed, there is a tendency to test new evidence against that explanation rather than reopening the underlying question.

 

The same problem on both sides

The difficulty becomes greater where the same process occurs on both sides of the dispute. Each legal team may rely on its own expert to understand the technical background and construct a coherent case. Each expert’s interpretation may then become incorporated into the respective pleadings and the court is eventually presented with two competing technical narratives, each defended by the expert who helped formulate it. At that stage, the experts may appear independent in form but may lack sufficient distance from the case theories they helped create.

Instead of receiving two objective opinions applied to the same facts, the Court may receive two opposing reconstructions built from different assumptions and developed alongside the parties’ cases.

The experts may no longer be testing the competing explanations. They may simply be defending them.

 

The importance of distinguishing roles

One way of addressing the problem is to distinguish clearly between the expert who advises the legal team and the expert who gives evidence to the court.

A consulting expert may help counsel understand the subject matter, identify relevant issues and test possible case theories. A separate testifying expert may then review the evidence and form an independent opinion without having helped construct the pleaded case.

An expert who has provided preliminary advice should not assume that those early views remain correct. When preparing a formal report, the testifying expert must reconsider the issues independently, based on the full evidence and the questions requiring expert opinion.

The earlier advice should be treated as provisional rather than as the starting point that must be defended.

 

Assumptions must remain visible

A further risk arises when assumptions supplied by counsel become absorbed into the expert’s own analysis. An expert may be asked to proceed on the basis that certain facts will be established. Expert opinions frequently depend on disputed facts that the court has not yet determined. The difficulty arises when the assumptions are no longer clearly identified.

A proposition that began as an instruction from counsel may gradually appear in the report as part of the expert’s own factual analysis.

The reader may then be unable to distinguish between:

• facts established by the evidence;
• assumptions supplied by the instructing lawyers;
• inferences drawn by the expert; and
• opinions properly falling within the expert’s expertise.

These distinctions are especially important where the expert has been involved in developing the case from an early stage.

The expert report should make clear which conclusions depend on assumptions and how the opinion would change if those assumptions were not accepted.

 

The expert must reopen the question

Where an expert has been involved from an early stage, the formal report should not merely document the advice already given; the expert should reopen the central questions.

That means reconsidering whether the original interpretation remains justified, whether contrary evidence has emerged and whether the pleaded case accurately reflects the expert’s present opinion.

Useful questions include:

• Did this conclusion originate from the evidence or from my preliminary advice?
• Has the conclusion been independently tested against the full documentary record?
• Am I being asked to support a proposition that I helped formulate?
• Have assumptions supplied by counsel been clearly identified?
• Would I reach the same conclusion if the pleadings had been framed differently?
• Have I considered whether the opposing interpretation is technically or commercially plausible?
• Am I expressing an expert opinion or resolving a disputed question of fact?

These questions are particularly important where the expert’s earlier advice has influenced the pleadings or the preparation of factual evidence.

 

The role of the instructing lawyers

Experienced legal teams recognise the risks created by relying too heavily on an expert’s preliminary views. Early expert assistance can help shape a case, but it should not be treated as a substitute for factual evidence. Counsel should distinguish between technical explanation, provisional opinion and established fact. They should also avoid placing the expert in a position where rejecting or qualifying an earlier view appears to undermine the entire case. A strong legal team will encourage the expert to revisit the original analysis once disclosure is substantially complete and the factual evidence has developed and may even amend the case where the expert’s independent review produces a different conclusion.

The purpose of early expert assistance is to improve understanding, not to predetermine the opinion that will later be given to the court.

 

The court’s need for independent assistance

The court does not need experts merely to present technically sophisticated versions of the parties’ arguments, it needs assistance that is independent of those arguments. Where experts have become closely involved in constructing the respective cases, there is a risk that the court is left to choose between two entrenched positions without receiving a genuinely detached analysis of the underlying technical issues. That is especially problematic in cases where the subject matter is highly specialised and the court is heavily dependent on expert assistance. The expert must therefore preserve enough distance to test the case rather than simply explain and defend it.

Early involvement can make an expert more useful, because it gives them a deep understanding of the evidence and issues, but it can also make independence more difficult.

The expert’s role is not to create the case and then validate it, it is to assist counsel in understanding the issues while remaining capable of giving the Court an opinion that is genuinely independent of the case ultimately pleaded.

 

Simon Bird – Partner

srb@objectivus.com

+44 (0) 7990 584 285