Paul Diver

Paul Diver, PhD, is a statistician, testifying expert witness, and managing director in BRG’s Washington, DC, office. He specializes in statistics, statistical sampling, extrapolation, econometrics, and the evaluation of complex sampling methodologies in litigation, arbitration, and regulatory matters.  

Dr. Diver has supported matters before federal and state courts, administrative law judges, regulatory commissions, and arbitration panels. He has been retained as an expert, submitted expert reports, and testified at trial in federal court, in state proceedings, and at arbitration hearings. He has also been deposed in federal litigation and arbitration matters. His expert work includes designing and drawing statistical samples, evaluating sample validity, and assessing extrapolation methodologies developed by opposing parties. 

Dr. Diver has extensive experience advising organizations and their counsel on statistical sampling and extrapolation. His analyses have been used across industries including healthcare, artificial intelligence, product liability, retail and luxury goods, waste collection and disposal, and live entertainment. His analyses include estimating potential fraud exposure and damages, conducting False Claims Act assessments, evaluating putative-class determination methodologies in class action matters, and estimating diagnosis upcoding rates, repayment amounts, and compliance risk. He also frequently assists clients in determining whether samples and associated extrapolations provide a statistically valid basis for broader conclusions. 

Dr. Diver’s work includes designing and evaluating statistical samples for healthcare organizations subject to Office of Inspector General corporate integrity agreements and evaluating Centers for Medicare & Medicaid Services (CMS) Risk Adjustment Data Validation audit sampling and extrapolation methodologies. He has also evaluated potential bias in the CMS Hierarchical Condition Category risk-adjustment model and the application of the associated fee-for-service adjuster. In addition, he advises clients on internal quality-control procedures, compliance monitoring, and statistical outlier detection. 

Dr. Diver has designed and implemented statistical samples independently for individual parties, collaborated with opposing experts to develop mutually acceptable sampling designs and statistical methodologies, and served as a neutral statistical expert jointly retained by opposing parties. 

Dr. Diver routinely applies a range of statistical and econometric techniques, including regression analysis, cluster and classification analyses, synthetic control methods, difference-in-differences analysis, and nonparametric methods. He also has experience analyzing large datasets using parallel-processing techniques.