Arroyo & Ors v Equion Energia Ltd

Expert evidence should be admitted where it may assist the court on issues in dispute and is reasonably required for the fair resolution of the proceedings. The court may assess admissibility provisionally where the evidence is potentially useful, leaving reliability and weight for trial. An expert’s experience, rather than formal membership of a specialist body, is the relevant indicator of expertise. Limited overstatement or material outside the pleadings does not necessarily require exclusion, particularly where the evidence can be managed and responsive evidence permitted.

The claimants applied for permission to rely at trial on a revised report by Mr David Willis, an engineer with experience in pipeline projects. The defendant objected that the report was not reasonably required, was irrelevant or inadmissible, exceeded the proper role of an expert, did not address pleaded allegations, and would cause substantial additional expense.

The court considered whether the report could assist in resolving issues concerning pipeline project and engineering management, whether Mr Willis was suitably qualified, and how any unpleaded or inadequately addressed matters and responsive evidence should be managed.

1. Permission granted. The report was admitted for use at trial because it contained opinions capable of acceptance which might assist the court. The court was not prepared at that stage to conclude either that Mr Willis lacked proper expertise or that the report contained no material assistance.
2. Expertise is not determined by formal membership of specialist associations or institutes. Mr Willis’s lengthy professional experience, chartered engineering status and experience in pipeline work were sufficient to qualify him to give evidence on the matters in issue. The reliability and authority of his opinions could be tested if he gave evidence.
3. An expert must respect the distinction between the expert’s function and the court’s function. Although parts of the report went beyond the proper limits of expert evidence or were unhappily phrased, a fair reading showed an attempt to remain within proper bounds. Such defects did not justify exclusion at this stage.
4. Some assertions appeared not to relate to pleaded issues. That could waste time and create difficulties for the opposing party, but the problem was manageable and did not require refusal of permission. The defendant could decide whether to respond, and additional cost was not prohibitive in the context of the proceedings.
5. The defendant was given permission to serve responsive factual or expert evidence within two months. That evidence had to identify whether it addressed a pleaded allegation, with the relevant pleading section, or an unpleaded matter raised in the report, with the relevant report passage. The permission did not extend to opening a generalised new front. Any later admissibility dispute concerning responsive evidence was left for determination at a further hearing.