Defense class-certification antitrust economist
Expert class library · Antitrust · Defense side
Attacks the plaintiffs' common-impact and damages models by showing individualized pricing and uninjured class members. Tests whether the plaintiffs' regression produces false positives or masks variation across customers.
What this expert is retained to answer
- Does the plaintiffs' regression find overcharges for customers who could not have been harmed?
- How many class members show zero or negative overcharges when the model is run customer by customer?
- Do individual negotiations and varied pricing make impact an individualized question?
- Is the plaintiffs' damages model consistent with their theory of liability?
Methods
- Uninjured class member analysis
- Disaggregated regression testing
- False positive testing
- Individual negotiation evidence review
How the testimony is attacked
- Uninjured member counts built on the opponent's own model. Plaintiffs argue that labeling customers with negative estimated overcharges as uninjured is unreliable. In Rail Freight the court admitted two defense economists' uninjured-member exercises because they used the same data as the plaintiffs' model.
- Using the wrong data to rebut a but-for analysis. Plaintiffs contend a defense economist cannot rebut a but-for price and output analysis with actual output data. In Mushroom the court excluded a defense report to the extent it did exactly that.
- Legal conclusions about certification. Courts do not let economists opine on whether a class should be certified. The Mushroom court excluded the defense economist's opinion to the extent it reached that legal conclusion.
- Critique goes to weight, not admissibility. Plaintiffs argue defense criticisms of their regression raise merits questions for the jury. In Olean the en banc Ninth Circuit affirmed certification after the district court weighed the defense economist's serious critique and left the dispute over uninjured members for trial.
- Customer-level testing that slices the data too thin. Plaintiffs answer disaggregated tests by arguing small customer-level samples produce noise rather than evidence of no injury. In Rail Freight the plaintiffs' rebuttal statistician responded to the defense uninjured-member critique by adding an indicator variable for each customer to the model.
What the public record shows
A deliberately narrow CourtListener search, "uninjured" AND "class members" AND regression AND antitrust AND (Daubert OR "Rule 702"), returned 14 opinions filed since 2015, as of October 2, 2026; broader searches return more. Three that show how courts handle this class of testimony:
| Outcome | Case | Court | Why |
|---|---|---|---|
| Admitted | In re Rail Freight Fuel Surcharge Antitrust Litig.292 F. Supp. 3d 14 | D.D.C. 2017 | The court found the defense economists' exercises identifying shippers with no or negative overcharges reliable under Rule 702 because they were built on the plaintiffs' own data and model, and later relied on them in denying certification. |
| Limited | In re Mushroom Direct Purchaser Antitrust Litigation319 F.R.D. 158 | E.D. Pa. 2016 | The court had denied the plaintiffs' motion to exclude one defense economist but excluded a second defense report to the extent it used actual output data to rebut the plaintiffs' but-for analysis and opined on whether the class should be certified. |
| Admitted | Olean Wholesale Grocery Co-Op v. Bumble Bee Foods LLC31 F.4th 651 | 9th Cir. 2022 | The en banc court affirmed class certification, holding that the district court properly considered the defense economist's critique that the plaintiffs' model counted many uninjured purchasers as injured, rather than merely asking whether the plaintiffs' model was admissible. |
Each case links to the free opinion text on CourtListener.
Under amended Rule 702
Since December 1, 2023, Rule 702 says expressly that the party offering an expert must show the court it is more likely than not that the testimony meets each requirement: that it rests on sufficient facts or data, uses reliable methods, and reflects a reliable application of those methods to the case. Questions about the basis of an opinion are no longer automatically matters of weight for the jury. For how the circuits have applied the amendment, see the Rule 702 tracker, which follows each court of appeals; for what that means for preparing or attacking this class of expert, see the guide on amended Rule 702.
Related classes
- Plaintiff common-impact economist
- Cartel-overcharge damages economist
- Indirect-purchaser pass-through economist
Guides
- Common Impact and Pass-Through at Class Certification
- Amended Rule 702 After Nearly Three Years: What Courts Exclude
Simulating this class on a matter
Supreme Mind simulates a class of expert, never a named individual, on your fact pattern and returns the likely opinion, the ranked cross-examination weaknesses, the Rule 702 attack surface and what it means for settlement. Read how it works, or book a demo.
Last reviewed October 2, 2026. How this page is built: rulings are found by searching court opinions on CourtListener, and each one is read in the opinion before it is summarised here; outcomes are labelled by what the court did with the expert's testimony. No individual expert is named. This page summarises public decisions for orientation and is not legal advice; read the opinion before relying on any ruling.