Part 3 – Comprehensive “Figures-as-Figures” assessments: Myth or legend?

Introduction and overview

This article addresses what the authors consider as a persistent issue in international construction disputes: the lack of a common understanding – or in some cases, the outright avoidance – of “figures-as-figures” assessments by expert witnesses.^[1]For this article we will focus on quantum experts as in our experience this is where the issue most extensively arises This term, which has seemingly evolved through practice rather than formal doctrine, refers to the presentation of alternative outcomes based on a range of potential findings by the tribunal on liability, methodology, and fact.

In our view, figures-as-figures analysis should be “business-as-usual” for expert witnesses,^[2]See Part 2 where we discuss the issue in the context of the use by the tribunals of party-appointed expert witness post-closing submissions yet too often, the concept of figures-as-figures is misunderstood, overlooked or even resisted. Our experience is that many tribunals (often jurisdiction led) prefer fully calculated answers from expert witnesses for each potential answer, and so those tribunals are left issuing unnecessary procedural directions and spending valuable hearing time attempting – often unsuccessfully – to extract information that expert witnesses should have provided as part of their overriding duty to assist the tribunal. Where tribunals do not receive the figures-as-figures assessments they require, they may (post-closing submissions) be left to appoint the party-appointed expert witnesses, as discussed in our previous article.^[3]See Part 2 – The use by tribunals of party-appointed expert witnesses, post-closing submissions – what happens and why?

The authors of this paper (Michael Tonkin^[4]Michael Tonkin is a Partner and Quantum Expert based in HKA’s Dubai office. Michael has acted as a lead expert on 75+ occasions and has been appointed arbitrator on over 65 matters. Michael is … Continue reading and Igor Corelj)^[5]Igor Corelj is a Partner and Quantum Expert based in HKA’s Dubai office. Igor has acted as a lead expert on 19 occasions and has assisted on more than 25 complex engineering and construction … Continue reading are both seasoned quantum expert witnesses, with over 50 years of combined experience in the international construction industry. Between them, they have been appointed as lead quantum experts on more than 95 matters. The views set out herein are grounded in their collective professional experience and a desire to enhance the quality and efficiency of expert witness evidence in complex construction disputes.

What does “figures-as-figures” mean?

Despite its use in practice, the term figures-as-figures appears to lack any known authoritative definition in either case law^[6]Limited to the authors’ understanding of the case law of England and Wales or published expert guidance.^[7]The authors would welcome this While the concept has been referenced,^[8]See, for example, Battersea Project Phase 2 Development Company Ltd v QFS Scaffolding Ltd [2024] EWHC 591 (TCC) it appears not to have been formally defined. The Academy of Experts offers some direction, noting that such assessments “revolve around different methodologies and facts the expert witnesses may use,”^[9]The Academy of Experts Guidance Note on Joint Statements, point 17 and footnote 4 but this guidance is neither comprehensive nor widely cited.

In our experience, colloquial meaning is that figures-as-figures are assessments that are without prejudice (to liability). This is broadly correct, but issues arise when quantum experts attempt to define more precisely what the term encompasses and what they should actually be doing. This article seeks to bring much needed clarity to the issue.  

We propose that figures-as-figures assessments are best understood as expert witness assessments based on a given premise / contingent scenario, based on the facts and / or the law – i.e. quantifications provided not solely on the expert witness’ preferred assumptions, but also on a range of alternatively pleaded legal and factual positions that the tribunal may adopt.

Proposed solution: a three-limb framework

To bring structure to the concept, we propose a simple analytical model based on three “limbs”, as follows:

• Limb 1: Liability – Do the parties agree on the contractual or legal basis for entitlement?
• Limb 2: Methodology – Do the parties adopt the same basis for quantification (e.g. contract rates, actual cost, quantum meruit)?
• Limb 3: Facts – Do the parties agree on the relevant facts (e.g. scope completed, quantities delivered, or records available)?

Where all three limbs are aligned, there is no dispute requiring expert input – save, perhaps, for the perfunctory application of an agreed methodology.

However, where any one or any combination of the three limbs is disagreed, the expert witness’ role is to assess each scenario arising from those disagreements, and to present the resultant answer/s.^[10][1] Proportionality must be a consideration and is raised under the next sub-heading Put simply, if any of the three limbs change, then this results in different figures-as-figures assessments. This could lead to, and often does lead to, multiple valuation options, as illustrated in the following simple worked example.

Worked Example

Assume a dispute arises over the supply of iron:

• Limb 1 (Liability): The Claimant claims for delivery of 10 tonnes of iron; the Respondent alleges the iron was defective and denies liability.
• Limb 2 (Methodology): The Claimant asserts a contract rate of US$50/tonne; the Respondent argues for a quantum meruit valuation on the basis that no rates were agreed.
• Limb 3 (Facts): The Claimant says 10 tonnes were delivered; the Respondent says only 9 tonnes were received.

This scenario gives rise to several different outcomes. The expert witnesses should consider each outcome and provide the following figures-as-figures assessments:

1. If the tribunal finds that the Claimant delivered 10 tonnes of material defect free, and the agreed rate is US$50 per tonne, then the amount due is US$500.
   
2. If the tribunal finds that the Claimant delivered 9 tonnes of material defect free, and the agreed rate is US$50 per tonne, then the amount due is US$450.
   
3. If the tribunal finds that the Claimant delivered 10 tonnes of material defect free, and the experts agree a quantum meruit rate of US$40 per tonne, then the amount due is US$400.
   
4. If the tribunal finds that the Claimant delivered 9 tonnes of material defect free, and the experts agree a quantum meruit rate of US$40 per tonne, then the amount due is US$360.
   
5. If the tribunal finds that the material delivered by the Claimant was defective, and so no liability arises, then the amount due is US$0 (and in this case a dispute on methodology and quantities becomes irrelevant).

Although this is a simple example, the fundamental point is that irrespective of which party the tribunal finds in favour, the tribunal is equipped with the necessary information to make its award based on that outcome. Importantly, only Limb 2 (methodology) typically involves expert witness opinion. Limbs 1 and 3 (liability and facts respectively) are for the tribunal to determine: the expert witness simply applies each potential finding.

Complex disputes, compound scenarios

As disputes increase in complexity, so too does the number and range of figures-as-figures options. Conflicting factual evidence, disputed records, or ambiguous instructions etc. can each introduce multiple variables. In large construction claims – often comprising delay, disruption, variations, and termination – each head of claim may require its own matrix of legal, factual, and methodological outcomes.

While this can produce a proliferation of scenarios, it is precisely here that the benefit of a common understanding of figures-as-figures becomes clear. Rather than presenting one definitive answer, expert witnesses can offer a decision tree of outcomes.

Many tribunals are apprehensive about undertaking technical assessments relating to matters such as delay, quantum, or engineering. Yet it is rare for one expert witness to be entirely correct on all matters, meaning that expert witnesses must assist tribunals as effectively as possible. This raises an important question – one we will examine in a future article – concerning the extent to which a tribunal ought to engage with expert witnesses in advance of the evidentiary hearing, particularly in relation to the figures-as-figures assessments it may require. Where such engagement does take place, a further question arises as to the appropriate scope and limits of that involvement.

In construction arbitrations, such figures-as-figures assessments are often extensive and costly, which we view as a concern. We believe early tribunal involvement should mitigate this, as well tribunals who are comfortable and understand the technical issues.

In our view the above also supports the case for bifurcating quantum (both in terms of liability and / or fact determinations), a step that is rarely taken but, in our view, warrants greater consideration.

Why are some expert witnesses reluctant to engage with “figures as figures”?

In our experience, and despite its value to the process, many expert witnesses resist providing figures-as-figures assessments, either in limited form or at all. The question is: why?

First, expert witnesses worry about decontextualised figures being misunderstood or misrepresented. Numbers rarely exist in a vacuum; the reliability of any output depends not only on the arithmetic or logic applied, but also on the soundness of the underlying evidence and assumptions. For many expert witnesses, being asked to validate figures without commenting on the assumptions that drive them, poses a risk. It may open the door to their work being misunderstood, misrepresented, or even selectively quoted in cross-examination. Expert witnesses are understandably [but wrongly] wary of being seen to endorse the integrity of a model or number that is not their own.

Second, from a practical standpoint, figures-as-figures exercises can be deceptively burdensome. This often entails a deep dive into another party’s financial model or spreadsheet, navigating unfamiliar methodologies and reverse-engineering complex calculations. Despite its surface simplicity, the exercise may require substantial time and effort, as well as often requiring tribunal support in terms of accessing documents – something clients may not anticipate or budget for or be willing to fund.

Third, someclients may resist such analysis altogether, particularly if it risks giving the appearance of lending support to an opposing party’s approach. Expert witnesses caught in the middle may hesitate [wrongly] for fear of overstepping their remit. Unfortunately, some expert witnesses may also receive instructions that they are not to provide opposing expert’s figures-as-figures assessments, an instruction which in our view should be resisted.

Yet, when properly qualified, figures-as-figures assessments do not amount to endorsement. They simply test whether the numbers make sense under different stated positions – an essential part of the expert witness’ duty of independence and assistance to the tribunal.

Common pitfalls to avoid

A recurring issue in expert witness evidence is the presentation of “Nil” assessments. This is where expert witnesses opine that no compensation is due solely because their client denies liability.

This approach risks undermining the expert witness’ independence and can appear to be more aligned with advocacy rather than analysis. The role of an expert witness is to assist the tribunal by providing valuations of Parties’ cases under a range of possible outcomes, not only those that support their client’s case.

Equally problematic is the failure to clearly explain the assumptions behind each valuation. Where figures are contingent on specific or factual findings, this should be clearly stated, and restated in any future updates. Without such clarity, there is a risk that the tribunal may misinterpret the basis of the assessment or apply it in an unintended context.

The timing of figures-as-figures assessments also warrants careful consideration. Introducing figures-as-figures for the first time at the start of the hearing may cause unnecessary disruption and limit the opportunity for meaningful engagement between the expert witnesses. A more effective approach is to raise these scenarios well in advance, ideally prior to the joint expert witness meetings, so they can be discussed, incorporated into the joint expert witness report, and addressed efficiently at the hearing. This allows the agreements and disagreements to be clearly defined and enhance the overall quality and transparency of the expert witness evidence.

Conclusion and summary

At the heart of a figures-as-figures assessment lies a seemingly straightforward request: the expert witness is asked to validate or critique the accuracy of calculations, independently of the factual assumptions and liability underpinning them. In essence, the task is to confirm whether, assuming the inputs are taken as correct, the resulting assessments (i.e. figures) are accurate.

“Figures-as-figures” assessments are not optional niceties, rather they are a fundamental aspect of objective, “decision-ready” expert witness evidence. Done well, they promote clarity, reduce procedural delays, and enhance the tribunal’s ability to make an award. Tribunals need to alert to the issues raised above and the challenges they bring and provide guidance to the expert witnesses as required.

Yes, concerns around misuse, scope, or cost are real – but they are surmountable. And the benefit of engaging in structured, transparent figures-as-figures analysis far outweighs the risks. This is not myth, nor legend – it is simply good practice, and it should be “business as usual” for expert witnesses.

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About the authors

Michael Tonkin is a Chartered Quantity Surveyor, Chartered Arbitrator, RICS Accredited Expert Witness and CEDR Accredited Mediator with over 30 years of construction industry experience. He is an effective dispute resolver and has acted as quantum expert on more than 40 occasions.

Igor Corelj is a Chartered Quantity Surveyor and structural engineer with over 15 years of international construction industry experience. He has acted as a quantum expert six times and has assisted the named expert on numerous occasions.