Building a Claim by Extrapolation – The Legal and Evidential Blocks

His Honour Judge Stephen Davies

June 2022

A paper presented to a meeting of the Society of Construction Law in London on 7th June 2022

The paper considers the use of sampling and extrapolation in court cases. The author sets out the ways in which it may arise and goes on to focus on its use in the case of Building Design Partnership Ltd v Standard Life Assurance Ltd. In that case Lord Justice Coulson accepted that it was possible to plead an extrapolated claim in an appropriate case, and indeed in that case it was a proportionate way to address a large number of variations. The author looks to his own experience in Amey LG Ltd v Cumbria County Council and examines the effect of extrapolation, whether or not it is pleaded, on case management, how the sampling exercise should best be managed and the question of the need for statistical evidence in such cases. He ends with a note of caution: don’t assume that succeeding in such a case will be plain sailing.

1. Overview – 2. Pleading – 3. Facts of Standard Life – 4. Court of Appeal Judgment – 5. Opening the floodgates – 6. Case management – general observations – 7. Case management – the approach even if sampling and extrapolation is not pleaded – 8. Case management – the sampling exercise – 9. Case Management – expert and other evidence – 10. Necessity for statistical evidence? – 11. Trial – expert evidence – 12. A similarity with global claims? – 13. Extrapolation in professional negligence claims? – 14. Final words of warning

The author: His Honour Judge Stephen Davies is a Judge of the Technology and Construction Court based in Manchester.

Text: 9 pages