Understanding the difference between quantum and delay expertise, and when each is needed, is essential for framing construction claims and instructing the right experts from the outset.
Quantum vs Delay vs Forensic Engineering
Construction disputes involve three distinct but related expert disciplines. Quantum experts (typically MRICS or FRICS chartered quantity surveyors) value the financial impact of claims, loss and expense, variations, prolongation costs, disruption, and final account disputes.
Delay experts (construction programmers) analyse the project programme to determine causation and entitlement to extensions of time. They use methodologies including Time Impact Analysis (TIA), windows analysis, and as-planned vs as-built comparison.
Forensic engineers (CEng) address technical failure, defects, design issues, and causation of physical damage or non-performance. Complex construction disputes often require all three disciplines working together to present a complete picture of entitlement and quantum.
Standard Form Contracts: JCT, NEC, and FIDIC
Forensic quantum experts must understand the specific contractual framework governing the dispute. JCT contracts (Design and Build, Standard Building Contract) contain detailed provisions on variations, loss and expense, and extensions of time that directly affect quantum analysis.
NEC contracts (NEC3, NEC4) use a different mechanism, compensation events rather than variations, requiring quantum experts familiar with NEC terminology and assessment procedures.
FIDIC contracts (Red, Yellow, Silver Books) govern most international construction projects and contain distinct provisions on claims, variations, and delay damages. Experts appearing in international construction arbitration must be familiar with FIDIC claim procedures and the role of the Dispute Adjudication Board (DAB).
Loss and Expense, Prolongation, and Disruption
Loss and expense claims compensate the contractor for costs incurred due to employer-caused delays or disruptions. Quantum experts quantify these costs by analysing site records, cost reports, and contemporaneous documentation.
Prolongation costs are the extended site overheads, preliminaries, and management costs incurred when the contractor remains on site beyond the original completion date. These are distinct from direct delay costs and require careful analysis of the contractor's cost records.
Disruption claims address loss of productivity caused by disruptive events, stacked trades, restricted access, or design changes, rather than overall project delay. The measured mile and other analytical techniques are used to quantify disruption losses.
Scott Schedules and TCC Practice
Scott Schedules are the standard format for presenting quantum and delay expert evidence in Technology and Construction Court proceedings. Each row sets out an individual claim item, the parties' respective positions, and the expert's opinion on entitlement and quantum.
TCC practice requires experts to exchange reports, meet to narrow issues, and produce a joint statement identifying agreed and disputed matters. The TCC Guide emphasises the importance of early expert engagement and the use of concurrent evidence (hot-tubbing) in appropriate cases.
Quantum experts appearing in the TCC should have prior testimony experience and be familiar with the TCC's case management approach, including the use of Scott Schedules and the requirements for expert evidence under CPR Part 35.
Adjudication and International Arbitration
Adjudication under the Housing Grants, Construction and Regeneration Act 1996 is a fast-track 28-day process requiring expert evidence to be prepared quickly. Quantum and delay experts must be able to produce focused reports within tight adjudication timetables.
International construction arbitration under ICC, LCIA, and FIDIC rules follows the IBA Rules on Evidence. Experts must produce reports addressing qualifications, instructions, methodology, and independence. Hot-tubbing is commonly used in major construction arbitration.
When instructing for adjudication or arbitration, ensure the expert has experience in the relevant forum and can meet the required timetable without compromising the quality of analysis.