Damages Proof and Expert Model Checklist: A Practical Checklist

Summary. A working checklist for the damages side of a civil case, run in the order the case runs: intake, preservation, pleading, discovery, expert report review before service, exclusion analysis against the other side's model, trial and verdict form items, and post-judgment interest, costs, and collection — with a defense column throughout.

For the doctrine, see Proving Damages in Civil Litigation. For the workflow narrative, see Building a Damages Case.

Phase 1 — The damages intake (week one)

What did this cost, in dollars, to date?
What will it cost going forward, and for how long?
What was spent because of the problem?
What was saved by not performing?
What was done to limit the loss, what did it cost, and why was that option chosen?
Which documents show each of the above, and who controls them?
Who else observed the effect (customers, employees, family, treating providers)?
What did the other side know about the consequences, and when did they learn it? (The foreseeability question — ask it in the first interview.)
Request the "before" documents immediately: 3 years of tax returns and financial statements; pay records; pre-injury medical records; prior invoices.
Collectibility check: assets, insurance, corporate structure, other creditors.
Cost-benefit: does the realistic recovery justify the cost of proving it? Say so now if not.

Phase 2 — Preservation

Litigation hold issued, covering damages data, not just liability documents.
Accounting system: general ledger, job costing, AR/AP, chart of accounts.
Sales and CRM data, including pipeline and lost-opportunity records.
Payroll, inventory, purchase orders, invoices, quotes.
Communications with affected customers and suppliers.
Snapshot key systems before any planned upgrade or migration.
Confirm the client retains the software and personnel needed to read legacy data.
Personal devices and messaging apps identified and preserved.
Defense side: sales data, unit-level P&L, and (if punitives are pleaded) net worth records.

Phase 3 — Pleading

Every category pleaded: general · special · consequential · incidental · statutory · fees · interest · costs · punitive.
Special damages itemized where Rule 9(g) or its state analogue requires specificity.
Foreseeability facts alleged: what was communicated, to whom, when.
Statutory basis for each statutory damages claim identified by section.
Basis for fee shifting (contract clause or statute) identified.
Punitive damages: heightened state of mind alleged; local prerequisites checked (leave of court, pre-suit notice, threshold showing).
Local rule on stating a specific dollar amount in the prayer checked.
For federal statutory claims, concrete harm pleaded independent of the statutory violation.
Defense: mitigation, setoff, limitation of liability, consequential damages waiver, statutory cap, comparative fault, collateral source, and any notice or presentment condition all pleaded as affirmative defenses.

Phase 4 — The damages theory memo (before discovery opens)

The legal measure for each claim, with citation.
The formula, written out, with placeholders.
For each placeholder: which document or witness supplies it, and who has it.
The but-for world and the evidence that establishes it.
Every alternative cause for the decline, and how the model addresses each.
The weakest link, named explicitly.
Fallback measures identified (reliance, restitution, statutory) and the evidence each would need.

Phase 5 — Discovery

Native-format production of accounting and sales data negotiated at the Rule 26(f) conference and reflected in the scheduling order.
Financial statements, tax returns, general ledgers — both sides, 3+ years.
Sales data by customer, product, and period.
Pre-dispute projections and budgets — especially those given to lenders, boards, or investors.
Documents on every alternative cause: departures, competitors, recalls, financing, regulatory action.
All mitigation documents, including opportunities declined and the reasons.
Insurance policies and claims relating to the same loss.
Third-party subpoenas to lost customers, lenders, and comparable-business sources.
Itemization interrogatory served early: each category, amount, method, and supporting documents.
Punitive damages financial condition discovery — timing rules checked.
Depositions taken of the controller/operator, not only the executive.
Lost customers deposed on why they left.
Cost behavior explored on the record: which costs varied with volume, which did not.

Phase 6 — Reviewing your own expert report before it is served

Every input traced to a Bates-numbered document or sworn testimony. Zero instances of "per management" standing alone.
The model isolates the conduct at issue — not firm-wide performance. (The Comcast fit problem.)
Alternative causes addressed affirmatively, not by silence.
Fixed versus variable costs analyzed from the financial statements, not assumed. Fixed costs that continued are not subtracted.
Semi-variable costs allocated by a supportable method (regression on historical volume), not by a round percentage.
Mitigation credit volunteered and computed.
Baseline period justified — and not cherry-picked from an unusually strong stretch.
Discount rate supported by a real-world source (the client's cost of capital, a lender's memo), not a textbook default.
Sensitivity analysis at three rates or three baseline assumptions.
Every assumption labeled as an assumption, with its source.
Arithmetic checkable by hand from the exhibits.
All opinions stated completely — nothing the expert intends to say at trial is missing.
Rule 26(a)(2)(B) formalities: qualifications, 10-year publications, 4-year testimony list, compensation, exhibits.
Expert's prior exclusion history searched and addressed.
Expert can explain the method in plain English without notes. Test this before service.

Phase 7 — Attacking the other side's model

Fit — does the model measure harm from the conduct still in the case?
Inputs — are they sourced, or supplied by the client unverified?
Alternative causes — are they addressed, or assumed away?
Cost treatment — were fixed costs improperly subtracted, or variable costs improperly retained?
Baseline — is the comparison period representative?
Mitigation — is the credit taken, and is it complete?
Methodology — has it ever been used outside litigation? By this expert? In a peer-reviewed or industry-accepted context?
Application — does the expert reliably apply the method to these facts? (Rule 702 as amended requires the proponent to show this by a preponderance.)
Analytical gap — is there "simply too great an analytical gap between the data and the opinion"? (General Electric Co. v. Joiner, 522 U.S. 136 (1997).)
Rule 703 — if the expert relies on inadmissible material, do experts in the field reasonably rely on that kind of material?
Motion framed around fit and application, not credentials.
Motion to exclude filed together with the damages summary judgment motion.
Rebuttal expert decision made: rebuttal-only, or an affirmative competing number?

Phase 8 — Settlement valuation

P(liability) × P(damages survive exclusion) × expected award, run at three award levels.
Fee-shifting exposure on both sides quantified.
Cost to verdict stated honestly, including expert and data-extraction costs.
Time-value discount applied.
Collectibility discount applied — assets, insurance limits, other creditors.
Damages exhibits (not the report) prepared for mediation.
Policy-limits demand considered where an insurer is defending; certified, with a reasonable deadline.

Phase 9 — Trial

Number stated in opening, with the reason for it.
One demonstrative per component: baseline · but-for revenue · avoided costs · mitigation credit · total.
Expert teaches the method before any number appears.
Assumptions, sensitivity range, and expert fee brought out on direct.
Summary exhibits prepared with underlying records available.
Non-economic damages built from specific, ordinary detail by disinterested witnesses.
Local rules checked on per-diem argument and the golden-rule prohibition.
Punitive damages: reprehensibility record built — duration, concealment, vulnerability, repetition.

Phase 10 — Instructions and verdict form

Reasonable certainty instruction distinguishing the fact of damage from the amount.
Wrongdoer-uncertainty instruction requested.
Mitigation instruction placing the burden on the defendant.
Punitive instruction consistent with Philip Morris USA v. Williams, 549 U.S. 346 (2007): nonparty harm may inform reprehensibility but may not be punished directly.
Verdict form itemized by category — past/future, economic/non-economic, consequential, statutory.
Interrogatories on disputed inputs added where post-trial attack is expected.
Bifurcation for punitive damages confirmed against local practice.
Comparative fault lines included; who applies the reduction confirmed.
All objections and refused instructions preserved on the record.

Phase 11 — After the verdict

Motion for prejudgment interest filed: rate, accrual date per component, simple or compound.
Bill of costs filed within the deadline (often 14 days) under Rule 54(d) and 28 U.S.C. § 1920. (Expert fees generally not taxable absent a fee-shifting statute.)
Fee petition prepared if a statute or contract shifts fees.
Remittitur/new trial opposition tied to the itemized findings.
Punitive award defended or attacked under BMW of North America v. Gore and State Farm v. Campbell — reprehensibility first, ratio second, comparable penalties third.
Judgment abstracted, recorded, and docketed in every relevant county and state.
Post-judgment discovery served immediately.
Garnishment, levy, and charging orders evaluated; fraudulent transfer review run.