Various Claimants v McAlpine & Ors

Expert evidence is admissible only where it concerns a recognised expertise governed by recognised standards and is capable of assisting the court on a relevant issue. Even evidence satisfying that threshold may be excluded where it will not materially help the court or where its admission would be disproportionate. Under CPR Part 35.1, proposed evidence must be reasonably required to resolve the proceedings. The court may refuse permission where methodology is insufficiently established, incompletely explained, difficult for the opposing party to scrutinise, dependent on further opaque stages, or not shown to be materially more useful than conventional methods.

The claimants in collective litigation concerning alleged construction-industry blacklisting applied for permission to rely on expert evidence estimating the earnings they might have received had they not been blacklisted. The proposed evidence initially involved a two-stage process using national earnings and employment data, industry evidence and individual adjustments. After an earlier hearing, the proposal was narrowed to a report by a labour economist based principally on regression analysis of NES/ASHE and Labour Force Survey data.

The court considered whether the evidence was admissible, whether it complied with CPR Part 35 and associated guidance, whether it would assist in resolving the issues, and whether the time, expense and data-access difficulties were proportionate.

The court dismissed the application.

1. Admissibility and relevance. Section 3 of the Civil Evidence Act 1972 permits qualified opinion evidence on a relevant matter, but the court must be satisfied that the proposed expertise and evidence can assist its decision. Evidence may still be excluded if it will not help the court. The proposed regression methodology was characterised as research, and the court was not satisfied that it met the recognised-expertise requirement (paras [61]-[63]).
2. Reasonably required evidence. CPR Part 35.1 required the evidence to be reasonably required to resolve the proceedings. The court concluded that the proposed approach was not shown to be sufficiently more accurate than traditional centile methods, particularly because it omitted prior earnings, lacked microdata for periods before 1990, and depended on a further individual-adjustment stage whose operation was insufficiently clear (paras [62]-[67]).
3. Compliance and fairness. Dr Butt’s contribution did not properly explain the facts, modelling, methodology, discussions or workings, contrary to CPR Part 35, Practice Direction 35 and the Guidance. Restrictions governing access to the ONS microdata created legitimate and potentially substantial difficulties for the defendants in testing the analysis (paras [64]-[65]).
4. Proportionality and completeness. The proposed stage-two adjustments could not safely be left to lawyers, and the stage-one work would not materially assist without them. The report also failed to address obvious alternative methodologies, including the earlier proposal and use of ASHE 90 with adjustments. The court therefore considered the time and expense disproportionate and dismissed the application (paras [63], [66]-[68]).

First-instance decision on the claimants’ application for permission to adduce expert evidence. The application had been considered at hearings on 14-15 July 2015 and was adjourned for further evidence before being dismissed following the hearing on 7-8 December 2015.