Biostatistician (meta-analysis)
Expert class library · Mass tort and product liability · Either side
A biostatistician or epidemiologist who pools results across clinical trials or observational studies to estimate whether a product raises risk, and critiques the other side's pooling choices. Courts accept meta-analysis as a reliable technique but exclude experts who apply it selectively, pick which studies to pool without explanation, or stretch pooled results to doses or groups the data do not cover.
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What this expert is retained to answer
- How were studies selected for pooling, and were the inclusion criteria set before the results were known?
- Was heterogeneity measured, and how did the expert handle studies whose designs or populations differ?
- Did the expert apply the same techniques to all the studies, or only to the subset that supported the opinion?
- Do the pooled results cover the dose, product and population at issue in the case?
- How does the expert treat results that are not statistically significant?
Methods
- Fixed and random effects meta-analysis
- Heterogeneity testing
- Publication bias assessment
- Sensitivity analysis
- Systematic literature search with predefined inclusion criteria
How the testimony is attacked
- Selective use of meta-analysis. Challengers show that the expert pooled only some studies and used looser methods for the rest. In In re Zoloft the Third Circuit affirmed exclusion of a biostatistician who ran a meta-analysis on just two studies without explaining why he did not pool the others.
- Inconsistent treatment of prior work. Opponents point to meta-analyses the expert relied on in earlier litigation but rejected here. In In re Zoloft the district court noted that the expert set aside meta-analyses he had relied on in a case about another drug of the same class.
- Pooled risk applied to the wrong dose. Defendants argue that a pooled association at high doses cannot be ascribed to low doses. In In re Lipitor the court admitted an expert's meta-analysis based causation opinion for the highest dose but excluded it for the lowest dose, where no study showed a significant association.
- Credibility choice disguised as gatekeeping. Proponents argue that disagreements over how to weigh pooled studies belong to the jury. In Carl v. Johnson and Johnson the New Jersey Appellate Division reversed the exclusion of experts whose opinions rested on several meta-analyses, including a new one by one of the experts, holding that the trial judge had chosen between competing experts.
- Statistical significance and trends. Experts who rely on nonsignificant results described as a trend face exclusion unless they explain why that is accepted practice. Zoloft upheld the finding that the expert's trend analysis was applied inconsistently and to support a conclusion reached in advance.
What the public record shows
A deliberately narrow CourtListener search, "meta-analysis" AND (causation OR "relative risk") AND expert AND (Daubert OR "Rule 702"), returned 68 opinions filed since 2015, as of October 3, 2026; broader searches return more. Three that show how courts handle this class of testimony:
| Outcome | Case | Court | Why |
|---|---|---|---|
| Excluded | In re Zoloft (Sertraline Hydrochloride) Products Liability Litigation858 F.3d 787 | 3d Cir. 2017 | The Third Circuit affirmed exclusion of a biostatistician's general causation opinion because, although meta-analysis, trend analysis and reanalysis are reliable techniques, he applied them selectively and inconsistently, including pooling only two studies without explanation. |
| Limited | In re Lipitor (Atorvastatin Calcium) Marketing, Sales Practices and Products Liability Litigation174 F. Supp. 3d 911 | D.S.C. 2016 | The court admitted an expert's causation opinion, built on a systematic literature search, his own meta-analysis and the Bradford Hill factors, for the 80 mg dose, but excluded it for the 10 mg dose because no study, including the only dose specific meta-analysis, showed a significant association at that dose. |
| Exclusion reversed | Carl v. Johnson and JohnsonNos. A-0387-16T1, A-0978-16T1 (N.J. Super. Ct. App. Div. Aug. 5, 2020) | N.J. Super. Ct. App. Div. 2020 | The Appellate Division reversed the exclusion of plaintiffs' epidemiology experts, one of whom performed a new meta-analysis of the talc and ovarian cancer studies, holding they used accepted methods and that the trial judge improperly chose between the experts' credibility. |
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
- General-causation epidemiologist
- Pharmacovigilance and signal detection expert
- Toxicologist (dose-response)
Guides
Simulating this class on a matter
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Last reviewed October 3, 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.