Adverse-Event & Pharmacovigilance Statistics Expert Witness
Independent statistical analysis of adverse-event and safety data for drug and device litigation — incidence-rate and safety-signal evaluation grounded in former FDA review experience and clinical-trial safety work. Available to plaintiff and defense, every engagement subject to a conflicts-of-interest check.
- Former FDA / CDRH statistical reviewer
- Clinical-trial & vaccine safety experience
- Incidence-rate & causal-inference methods
- Plaintiff & defense
Adverse-event disputes Dr. Li addresses
Adverse-event and safety questions turn on how rates are calculated, what they are compared against, and whether the underlying data can support the inference being drawn. Dr. Li works with counsel on the statistical issues below.
Incidence & AE-rate calculation
Computation and comparison of adverse-event incidence rates, risk differences, and relative measures across treatment and control or comparator groups.
Number needed to harm
Derivation and interpretation of number needed to harm and related absolute-risk measures, including their precision and limitations.
Safety-signal evaluation
Assessment of whether reported patterns constitute a statistically supportable safety signal or fall within expected background variation.
FAERS & spontaneous reports
The uses and well-known limitations of FAERS and spontaneous-reporting data, including reporting bias and the absence of a defined denominator.
Denominator & exposure issues
Person-time, exposure windows, and at-risk populations — how an ill-defined denominator distorts rate comparisons and conclusions.
Confounding & comparability
Whether compared groups are comparable, and how confounding or selection effects can drive apparent differences in adverse-event rates.
Trial safety analyses
Pre-specified safety analyses, multiplicity across many endpoints, and the strength of evidence from clinical-trial safety data.
Statistics vs. causation context
How statistical association relates to — and differs from — questions of specific causation, with reference to relative-risk reasoning. See relative risk and specific causation.
How Dr. Li helps
Work is scoped to the statistical and methodological questions in the matter, delivered in language counsel and triers of fact can follow.
Independent re-analysis of AE rates
Reconstruction and independent computation of adverse-event incidence and risk measures from the source trial, registry, or reporting data.
Critique of opposing safety analyses
Examination of an opposing expert's adverse-event or safety-signal methodology, including assumptions, comparators, and the limits of the supporting data.
Methodology & Daubert review
Assessment of whether a statistical safety method is reliably applied to the facts, supporting motions addressing admissibility and reliability.
Reports & testimony
Expert reports, declarations, and rebuttals. Dr. Li is available for deposition and trial testimony; engagements to date have been in a consulting capacity.
Relevant experience
Dr. Li's safety-analysis work spans regulatory review and clinical-trial practice. The following is provided for background only and is not a prediction of any result.
- As a former Mathematical Statistician and Primary Statistical Reviewer at the FDA's Center for Devices and Radiological Health (Sep 2020 – Apr 2022), Dr. Li reviewed statistical and safety evidence across PMA, De Novo, 510(k), IDE, and real-world-evidence submissions and authored statistical memoranda for therapeutic and diagnostic devices.
- As Statistical Project Leader at Sanofi (Jun 2023 – Apr 2025), he supported clinical-trial safety analyses and safety deliverables across vaccine programs, including phase I/II, phase III rabies, E. coli, and hemophilia studies with FDA and EMA regulatory activities.
- His methods experience includes adverse-event incidence analysis, causal inference and propensity scores, group-sequential and Bayesian designs, and permutation and survival methods, implemented in SAS, R, and Python.
Dr. Li is a former FDA / CDRH statistician and is no longer affiliated with the FDA. This site is not affiliated with, endorsed by, or sponsored by the FDA or any government agency. Disclosed litigation engagements to date have been in a consulting-expert capacity and are kept confidential and anonymized.
Frequently asked
Can a difference in adverse-event rates prove the product caused an injury?
A statistical difference in rates is an association, not proof of specific causation. Dr. Li can explain what a rate comparison does and does not establish and how it relates to relative-risk reasoning, while causation questions remain for the trier of fact and other experts.
Are FAERS or spontaneous-report counts reliable evidence of a safety problem?
Spontaneous-reporting systems such as FAERS are subject to reporting bias and lack a defined exposure denominator, so raw counts cannot be read as incidence rates. Dr. Li can describe their accepted uses and limitations in the context of a specific matter.
Will Dr. Li serve as a testifying expert?
Yes. Dr. Li welcomes testifying engagements, including reports, declarations, deposition, and trial. His disclosed engagements to date have been in a consulting-expert capacity.
Does Dr. Li work for plaintiff or defense?
Both. He accepts engagements from either side, subject to a conflicts-of-interest check before any work begins.
Discuss an adverse-event or safety analysis
Tell Dr. Li about the data, the disputed analyses, and your timeline. Initial consultations are confidential and subject to a conflicts check.