Options where (quantum) evidence is missing or is unreliable
NB figures in brackets are a reference to paragraph numbers in The Law of Damages
Highlighted text added June 2003

Where better quantum evidence is not obtainable, the court must do the best it can: Biggin and Co Ltd and Another v Permanite Ltd [1951] 1 KB 422; [1950] 2 All ER 859 (considered under Liability/Evidence as to Quantum/duty to adduce evidence), illustrated by Ashcroft v Curtin [1971] 1 WLR 1731; [1971] 3 All ER 1208, CA. and Thompson and others v Smiths Shiprepairers (North Shields) Ltd [1984] QB 405; [1984] 1 All ER 881, QBD (6.24-6.26).

If the court decides that a party was under a duty to maintain contemporaneous records and had not done so then it may, when making the assessment, give the benefit of any doubt as to quantum to the other party: eg Mustill J in Thompson [1984] 1 All ER 881 at 910:

"What justice does demand, to my mind, is that the court should make the best estimate which it can, in the light of the [incomplete] evidence, making the fullest allowances in favour of the plaintiffs for the uncertainties known to be involved in any apportionment."

Where better or more reliable quantum evidence is obtainable the court has the following options:

1. Best estimate on the basis of the evidence adduced
  1. Tai Hing Cotton Mill Ltd v Kamsing Knitting Factory [1979] AC 91; [1978] 1 All ER 515, PC - enquiry not ordered - sufficiently accurate assessment could be made - costs of enquiry would outweigh any additional certainty/accuracy in assessment (see 'Criteria' below).

  2. T J Newbrook and R K Newbrook v T & R Newbrook Limited & Ors [2001] NZCA 332 - an assessment of lost profits and of the portion thereof attributable to the breach could be made - Tai Hing Cotton Mill applied

If missing evidence is available but not adduced due to the fault of one of the parties or its representatives (the duty to the court with regard to adducing evidence is considered in the article on Liability/Evidence as to Quantum) it may be appropriate to give the benefit of any doubt as to quantum to the other party.

2. Use of own (expert) knowledge by judge/arbitrator/assessor

There may be no distinction between this option and the one above. A judge or arbitrator (or anyone assessing damages) is under a duty to use his/her own expert knowledge. There is however a potential issue as to whether it would be appropriate to invite representations/give the parties an opportunity to comment where expert knowledge is being used. The opportunity to comment cases generally involve some new matter raised by the judge or arbitrator upon which the parties have not had the opportunity to comment: see Annie Fox and Others v P.G. Wellfair Ltd (In Liquidation) [1981] 2 Lloyd's Rep 514, CA for a review of the law in this area. Unless there is a new finding of fact (eg AG v Shimizu, below) or some new matter introduced by the judge/arbitrator it could be argued that, where expert knowledge is used in the assessment of damages, no new issue is raised and the parties have already had the opportunity to comment on the matter. The only ground of appeal might therefore be that the assessment was wholly erroneous or clearly wrong: eg Watson v Powles [1967] 3 All ER 721, CA and Vulcan Engineering Co Inc v Fata Aluminium Inc and Fata Group SpA United States Court of Appeals for the Federal Circuit 00-1533. Examples of the court using its own expert knowledge where quantum evidence is missing include:

  1. Alger, Brownless & Court Copyservices Limited v Jitesh Thakrar Trading as Thakrar and Co (a firm) [1999] EWCA Civ 574

  2. Ministry of Defence v Cannock and others [1995] 2 All ER 449, Employment Appeal Tribunal. At 471, Morison J said that:

"There is a small, additional point in the case of Mrs Dill. Based upon its own knowledge, the industrial tribunal adopted a figure for child care of £30 per week. It is said that it was wrong to use its own knowledge, at least without having revealed the source from which that knowledge was derived. It seems to us that whilst industrial tribunals are, as industrial juries, entitled to use their own knowledge and experience when reaching decisions, they should be careful to ensure that parties know what is in their minds, so that the points can be addressed in argument. There is no suggestion that the figure it gave in this instance was wrong or excessive: it appears to be consistent with other figures in other cases and we are not minded to say that the industrial tribunal erred in law 471 or that Mrs Dill has been prejudiced by what happened. This issue was no longer live as a result of agreement between the parties. Accordingly we reject that specific cross-appeal."

3. Invite representations/further evidence from the parties
  1. Attorney General v Shimizu Corporation [1996] HKCFI 171 - finding of  fact by arbitrator which would have rendered the parties' submissions on quantum obsolete

  2. David Weeks v John Magill and Dame Shirley Porter v John Magill [1999] EWCA Civ 1317 - complex assessment/valuation of property case:

"In his note of preliminary findings issued on 13 January 1994 the auditor mentioned the sum of £21.255m as the sum which he had to consider certifying. At the audit hearings (held between 19 October 1994 and 7 February 1995) the auditor heard evidence (on behalf of Lady Porter) as to quantum from three accountants, Mr Wheeler of Chantrey Vellacott, Mr Aldous of Robson Rhodes, and Mr Swinson of BDO Stoy Hayward. There was no evidence as to the valuation of the 618 dwellings sold under the designated sales policy. The auditor also received supplementary statements from Mr Aldous and Mr Swinson in April 1995. On 17 August 1995 the auditor sent out a "revised provisional calculation" of loss supported by various appendices, and invited representations on them."

Where additional costs/fees are incurred as a result of failure to adduce relevant and obtainable quantum evidence (the duty to the court with regard to adducing evidence is considered in the article on Liability/Evidence as to Quantum), the court may make a costs/fees order against the appropriate party or its representatives. 

4. Order an enquiry as to damages
  1. Embrex, Inc., v Service Engineering Corp. And Edward G. Bounds, Jr., United States Court of Appeals for the Federal Circuit 99-1064 - assessment of damages for patent infringement - "In this case, the record does not supply sufficient evidence to compute a reasonable royalty as required by section 284. Therefore, this court vacates the award of $500,000 in direct damages and remands to the district court for determination of a reasonable royalty for SEC’s infringing uses of the patented method."

  2. Tse Kwong Lam v Wong Chit Sen and others [1983] 1 WLR 1349; [1983] 3 All ER 54, PC - Assessment - appeal - mortgagee selling at less than best price reasonably obtainable/market value - no evidence adduced/considered at trial in relation to change in values due to decline in property market (a factor which was found to exist) between April (evidence as to value available) and June 1966 (date of sale) - Held: case to be remitted to Court of Appeal to make such directions as may be considered necessary for the assessment of damages by the High Court

  3. Cuckmere Brick Co Ltd v Mutual Finance Ltd [1971] Ch 949, [1971] 2 WLR 1207, [1971] 2 All ER 633, CA - assessment of land value - residual method of valuation - evidence/method of assessment unreliable - better evidence obtainable - case remitted for enquiry as to damages

  4. Tai Hing Cotton Mill Ltd v Kamsing Knitting Factory [1979] AC 91; [1978] 1 All ER 515, PC - enquiry not ordered - sufficiently accurate assessment could be made - costs of enquiry would outweigh any additional certainty/accuracy in assessment.

As to additional cost implications, see the note at the end of option 3 above.

5. Deferral of assessment
  1. Trans Trust SPRL v Danubian Trading Co Ltd [1952] 2 QB 297; [1952] 1 All ER 970, CA - court has inherent jurisdiction to defer assessment

  2. Deeny and others v Gooda Walker Ltd (in liq) and others [1995] 1 WLR 1206; [1995] 4 All ER 289, QBD - prospective/future loss - assessment of future claims by third parties against insurers - unreliable/highly uncertain method of assessment - wide difference between experts as to amount - assessment deferred under rules of court alternatively inherent jurisdiction - interim award - indemnity considered


  1. The standard of proof - exact compensation is not required - can justice be served/a fair compensation be arrived at by making a guesstimate?: eg the Tai Hing Cotton Mill case, referred to above.

  2. Where there is a high degree of uncertainty/unreliability in the assessment, further investigation will be more likely. 

  3. The court should weigh the costs of carrying out further investigation/enquiry against the degree of additional certainty/accuracy obtainable: See Tai Hing Cotton Mill above at 1./Best Estimate. The point is also illustrated by National Association of Manufacturers v United States Department of the Interior, United States Court of Appeals for the District of Columbia Circuit 1998 No. 96-1268 - Claim for damages for damage to the environment - cheaper method (Type A) = assessment based on averages. Type B = more expensive/collecting site specific data:

"In deciding whether to use Type A or Type B procedures (or some combination of the two), the trustee must "weigh the difficulty of collecting site-specific data against the suitability of the averaged data and simplifying assumptions in the type A procedure for the release being assessed." 43 C.F.R. §§ 11.35(a) (1996). The trustee may elect to use Type B procedures if "they can be performed at a reasonable cost and if the increase in accuracy outweighs the increase in assessment costs." Id. Even if a trustee decides to use Type A procedures, a PRP may nonetheless insist on Type B proce- dures. See id. §§ 11.35(b); 1996 Type A rule, 61 Fed. Reg. at 20,562"

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