Trial testimony in a commercial contract dispute asks the economist to show the fact finder the but-for revenue, the incremental costs, the resulting lost margin, and the present value of the future portion, each traceable to the contract, the ledger, or the pre-dispute projections. Demonstratives should show revenue and margin by period, with replaced revenue credited, and a board should pair the discount rate with the risk it reflects. The opposing expert typically differs on but-for revenue, cost treatment, and the discount rate; the direct examination should explain each of those choices from the business's own records before cross.
Checklist
Prepare boards for but-for revenue, incremental costs, and lost margin by period
Prepare a board showing replaced revenue and its credit against the loss
Prepare the discount rate explanation and the total under the opposing rate
Prepare a comparison of the two experts' assumptions and what each difference moves
Confirm every board figure ties to a report schedule and a source document
Questions to ask the economist
How will you show that the but-for revenue rests on the business's records rather than its projections alone?
How will you explain incremental costs to a fact finder without an accounting background?
What does the total look like under the opposing expert's cost treatment?
How will you present the discount rate and the risk it reflects?
Timeline
One to two preparation sessions in the week before testimony, after the demonstratives are drafted and the opposing report has been analyzed.
Required documents
The final report with revenue, cost, and present value schedules
The contract, pre-dispute projections, and ledger detail relied on
Draft demonstratives
The opposing expert's report and deposition transcript
Common pitfalls
Presenting lost revenue as if it were lost profit
Showing a margin without the cost analysis that supports it
Explaining the discount rate as a formula rather than as the risk that the profits would have carried
How does the economist rebut an opposing expert who says the business would have failed anyway?
With the business's own pre-dispute record: its revenue trend, its margins, its customer base, and any projections it made before the dispute arose. The economist shows the but-for path under those facts and the total under the opposing expert's assumption, so the fact finder can decide which the evidence supports.
How does the economist present lost profits to a judge rather than a jury?
With the same schedules in less narrative form: but-for revenue, incremental costs, lost margin by period, replaced revenue credited, and present value, each tied to a source document. Judges often want the schedules organized so findings can be made line by line and the alternative treatments visible. The demonstratives can be the report's schedules themselves.
What if the fact finder accepts liability but not the damages period claimed?
The schedules show the loss by period, so a shorter period can be read directly from them without a new calculation. The economist should say so on direct, because it tells the fact finder that the figure is not all or nothing. The preparation session should confirm the by-period totals are on the boards.
References
American Institute of Certified Public Accountants. (n.d.). Statement on Standards for Valuation Services (VS Section 100). AICPA & CIMA. Retrieved August 27, 2026. aicpa-cima.com
U.S. Department of the Treasury. (n.d.). Daily Treasury par yield curve rates. home.treasury.gov
American Academy of Economic and Financial Experts. (n.d.). Journal of Legal Economics. Retrieved August 27, 2026. aaefe.org