The grounds that succeed are methodological, visible in the report, and mostly identifiable months in advance.
Start a conversation with Cournot, the Institute’s damages concierge, already scoped to daubert challenges to damages experts. Pick a starting point, or describe the dispute directly.
The admissibility framework asks whether an expert's reasoning is reliable and whether it fits the facts of the case. Applied to damages, that resolves into a small set of recurring questions: is there a discernible method, was it applied to these facts rather than in the abstract, are the inputs supportable, and does the conclusion follow from the analysis rather than from the assumption. Published research gives a sense of scale — a PwC study covering 2000 to 2021 reported roughly a third of challenges to financial experts producing at least partial exclusion — but the more useful observation for a practitioner is qualitative. The successful challenges cluster around a handful of failures that are legible on the face of a report, which means both sides of a case can assess exposure long before a motion is drafted.
Ordered roughly by how often they appear, not by how hard they are to fix.
A recognised method applied generically, without tying it to this business, market or conduct.
A counterfactual built on growth or market share the record does not support.
Attributing all of a result to the conduct without addressing what else caused it.
Inputs too thin, too aggregated or too unreliable for the conclusion drawn.
Opining on what the law permits rather than what the economics show. Associated with higher exclusion rates.
Assuming rather than analysing that the conduct caused the economic outcome measured.
How an opinion gets stress-tested.
In many postures, losing the damages expert is losing the ability to prove any number.
Nearly every ground that succeeds was visible in the report. The window to cure it — different method, more data, narrower opinion — closes when the report is served, not when the motion arrives.
It depends on what a win would actually achieve, and firms often skip that question. Where exclusion would leave the opponent unable to prove any damages, the motion can be case-dispositive and is almost always worth bringing. Where the likely outcome is partial — one method struck while another survives, or a category narrowed — the calculus is different, and a failed motion can leave the expert looking court-endorsed in front of the jury. The published rates suggest challenges succeed at least partly often enough to be taken seriously by both sides, which cuts both ways: it is also a reason to assume your own expert will be challenged.
Being explicitly tethered to the record, and being candid about its own uncertainty. A resilient opinion states the method, states why that method suits these facts, traces each material input to a document or testimony, addresses what else could have caused the outcome, and presents a range or sensitivity analysis rather than a single confident number. That last point is counterintuitive to lawyers who want a strong figure, but an expert who acknowledges how much the conclusion moves with a key assumption is considerably harder to destroy than one who does not and is shown the range on cross.
It depends on the posture and it is frequently severe. In matters where damages must be proved by expert testimony, exclusion can mean summary judgment or a nominal award regardless of how strong liability was. Sometimes a replacement expert is possible; often the scheduling order has closed that door. This asymmetry is the argument for treating the damages methodology as a first-order case decision rather than something delegated after liability strategy is set, because the downside is not a smaller number but no number.
Yes, and it matters enough to check at the outset rather than assume. States vary in whether they follow the federal reliability framework, an older general-acceptance approach, or something of their own, and the federal rule governing expert testimony has itself been amended in recent years to sharpen the court's gatekeeping obligation. Published exclusion statistics generally reflect federal practice, so their applicability to a state matter is a question rather than a given. This is squarely a legal question for counsel; the Institute can tell you what the frameworks ask of an expert, not which one governs your case.
Describe the opinion and its method. The Institute will help you find the weakest link.