How Good is Your Expert Evidence?


Obtaining a favourable outcome for a client involved in a property dispute very often depends upon the quality of the opinion evidence provided in support of their case. The most obvious instances are surveyors providing valuation evidence in the context of lease renewals and rent review arbitrations or surveying evidence in the context of dilapidation claims. More often than not, the outcome of the dispute turns upon how favourably the Judge or arbitrator views the evidence that each party provides. Consequently, it is essential to ensure that the expert evidence is of the best possible quality.

That starts with the expert himself. Does he have the necessary expertise to be providing expert evidence at all? This has three aspects: his qualifications, his experience in practice and his experience of providing expert evidence (both in reports and orally in court). As to the first, possessing a professional membership (most obviously of the Royal Institution of Chartered Surveyors) is essential. Many years experience in practice should be an adjunct of not a substitute for qualifications. Further, membership of the Academy of Experts or a similar body is more likely to convince the tribunal that the expert genuinely understands the requirements imposed on him; that is, providing evidence that is impartial and independent of the interests of the client by whom he is instructed.

Length of experience in the area of the subject- matter of the dispute provides greater weight to his opinion. Further, experience in report writing (in respect of which see further below) and the giving of oral evidence is likely to make the expert more aware of the pitfalls of providing evidence. Experts that have experience of being cross-examined (and have not been put off by the whole experience) are less likely to be rattled by questioning,

The next issue is whether or not the expert is genuinely independent of the parties. One recent experience (where a surveyor in a partnership was to give expert evidence in a lease renewal in respect of premises that the partnership was occupying and consequently being an issue in which he had a direct financial interest) indicates that parties do not always pay enough attention to the question of conflicts of interest. The presence of a conflict of interest does not automatically disqualify an expert. As the Court of Appeal has confirmed in Toth v Jarman [2006] 4 All ER 1276, the key question is whether or not the expert’s opinion is independent. Where the conflict of interest is material or significant, the court is unlikely to act on the evidence or indeed give permission for his evidence to be adduced. The safest course is simply to choose an expert in respect of whom there could be no appearance of a conflict of interest. However, if for some reason using such an expert is unavoidable, a potential conflict of interest should be disclosed in the report (along with an explanation as to why the potential conflict is immaterial, thus rendering the impartiality of the expert’s opinion unaffected).

Every expert that writes a report knows that he needs to follow the requirements of CPR 35 and the Practice Direction thereto. However, compliance in form (e.g. including the correct form of the statement of truth) must also be reflected in substance. The expert should be reminded not only before writing the report, but also before appearing in court, of the necessity of being thoroughly familiar with the requirements of his role. That is set out in CPR 35.3 (over-riding duty to the court). Flesh to the bones of that requirement is provided by the “Protocol for the Instruction of Experts to give evidence in Claims” (produced by the Civil Justice Council and annexed to CPR Part 35) and in the Practice Statement and Guidance Notes for Surveyors Acting as an Expert (produced by the RICS and currently in its second edition). The report should record that both these documents have been consulted and understood.

Once you are satisfied that the expert has taken this on board, the next question is the quality of the report itself. Most obviously this manifests itself in the quality of its reasoning. Surveyors (quite reasonably) never tire of saying that “Valuation is an art, not a science”. Quite right. However, it should not be the application of what a Judge recently called “pseudo-science.” So in the case of valuation for instance, any reliance upon a convention (e.g. “onerous alienation clauses always depress market value by 2%”) needs to be looked at very closely. It is the underlying reasoning for such a convention that needs to be explained and explained well. If the reasoning is lacking or defective, it provides more scope for cross-examination and undermines the effectiveness of the evidence.

Further, the production of empirical data (e.g. as to rental trends in a particular sector and area) can provide not only helpful evidence but also an indication of care and diligence on the part of the expert.

The other important aspect to note is that the report should be digestible i.e. well- structured and easy to read. Sometimes. Judges in the County Court will have had little time to read reports, so it is important that the contents of the report can be easily understood.

Apologies if all of this seems obvious. However, it is surprising how often an expert or his evidence falls short in some, if not all of the respects mentioned above. Taking care in instructing the expert and considering the contents of the report (and if necessary requiring amendments) may make all the difference between success and failure.

In Summary

  • When selecting an expert, check his qualifications and experience; membership of the RICS is essential and of the Academy of Experts desirable
  • Make sure the expert is independent
  • Make sure that when the expert says he has read and understood the guidance on his role, he really has and that this is reflected in the content of his report
  • Ensure the report is a quality product and request amendments, if necessary.

James Hanham
9 Stone Buildings