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department of admissibility & challenge

Around a third of challenges to financial experts succeed at least in part.

A study covering 2000–2021 put partial or complete exclusion at roughly one in three. The damages opinion is not the safe part of the case.

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What is the economic harm?

Start a conversation with Cournot, the Institute’s damages concierge, already scoped to admissibility & challenge. Select a subject area to prompt it, or describe the dispute directly.

Cournotadmissibility & challenge · a diagnostic, not a damages opinion
Tell me whose opinion we're looking at and what method it uses. I'll help you think about where it is exposed. I won't predict what your judge will do, and I won't tell you what the law requires.

Firms treat liability as the contested half of a case and damages as arithmetic that follows. The admissibility record does not support that. Research by PwC covering challenges from 2000 to 2021 found that roughly a third of Daubert challenges to financial experts resulted in at least partial exclusion — and the pattern within that figure is instructive: experts whose opinions read as legal conclusions were excluded at higher rates, while lost-profits analyses fared comparatively better than some other categories. An excluded damages expert does not merely weaken a case; in many postures it removes the ability to prove any number at all, after the liability work is already paid for. The failures that produce exclusion are largely methodological and largely foreseeable, which means they are largely avoidable if someone looks early.

specialization areas

Areas in this part of the practice.

What gets excluded and why, how to read the other side’s report, and the data foundation underneath both.

methodology

How this department investigates.

How the Institute approaches admissibility — the framework and the record, never a prediction about your judge.

Reading the exclusion recordWhat the studies measured, over what period, and what that does and does not tell you.
Fit to the factsWhether the methodology is tethered to this case or applied generically, which is a recurring basis for challenge.
Data foundationWhether the inputs exist, are reliable, and support the weight placed on them.
Apportionment disciplineWhether value attributable to the conduct is separated from value that is not.
The legal-conclusion lineWhere an economic opinion crosses into telling the court what the law requires.
Sensitivity and rangesWhether the opinion acknowledges how much its conclusion moves with its assumptions.
common questions

Admissibility — the questions counsel ask.

How often are damages experts actually excluded?

More often than most litigators assume, and the honest answer carries a date and a source. PwC research covering challenges from 2000 through 2021 found roughly a third of challenges to financial experts produced at least partial exclusion. "Partial" matters — an expert may survive while a particular opinion, method or damages category is struck, which can still gut a claim. Rates vary by the type of analysis: opinions that read as legal conclusions drew exclusion at higher rates, and lost-profits work fared comparatively better than some other categories. Treat any single figure as describing the period it measured rather than as a fixed property of the field.

What actually gets an opinion excluded?

Rarely the arithmetic; usually the connection between the method and the case. The recurring failures are an approach applied generically rather than fitted to these facts, a counterfactual resting on assumptions with no evidentiary support, failure to apportion value between the conduct and everything else that drove the result, reliance on data that does not bear the weight placed on it, and opinions that answer legal questions rather than economic ones. What these share is that they are visible in the report. An experienced reader can usually see the vulnerability months before the motion is filed.

When should admissibility be considered?

Before the expert is retained, which is earlier than most firms think about it. The choice of measure determines what data is needed; the data determines whether the method can be supported; and the method is what gets challenged. A firm that selects an expert, lets them choose an approach, and only considers admissibility when the opposing motion arrives has sequenced the case backwards. The cheapest point to fix a methodological vulnerability is before any modelling has been done, and the most expensive is after a report has been served.

Does surviving a challenge mean the number is sound?

No, and conflating the two is a common error. Admissibility asks whether the opinion is reliable enough for a fact-finder to hear it; it does not ask whether it is correct. An opinion can be admitted and then thoroughly dismantled on cross, or simply disbelieved. Conversely, an opinion excluded on a technical ground may have been substantively reasonable. The practical implication is that clearing the admissibility bar is a floor, not a finish line, and firms that treat the denied motion as vindication tend to under-prepare the expert for the part that actually decides the number.

Find the vulnerability before they do.

Describe the damages opinion — yours or theirs. The Institute will help you see where it is exposed.

Cournotdiagnostic · not a damages opinion
Tell me whose opinion we're looking at and what method it uses. I'll help you think about where it is exposed. I won't predict what your judge will do, and I won't tell you what the law requires.