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Scientific Evidence of Factual Causation
An Educational Module

Steve C. Gold
Professor of Law
Rutgers School of Law-Newark
Michael D. Green
Williams Professor of Law
Wake Forest University School of Law
Joseph Sanders
A.A. White Professor of Law
University of Houston Law Center

Factual Causation

This module examines three scientific areas that provide evidence bearing on causation in the “toxic tort” or environmental disease context: epidemiology, toxicology, and genetics. These scientific disciplines are used in civil lawsuits and in regulatory proceedings in which causation or risk is an issue. The module is appropriate for non-scientist law students as well as others interested in learning the science of toxic tort causation, including practicing attorneys, judges, and public policy and public health students in the United States and elsewhere. It is designed to provide the following core competencies: 

  1. An understanding of the concept of factual causation and how evidence bearing on that matter is brought to bear in judicial proceedings and the regulatory context.
  2. How the results of an observational epidemiologic study bear on factual causation and the methods and limitations of studies in providing proof of causation.
  3. Outcome measures of relationships found in epidemiologic studies, the role of random chance, bias and confounding in skewing those relationships, and the process of determining whether a correlation is causal or spurious. 
  4. The difference between epidemiology and toxicology and the latter’s focus on whether and how a suspected toxic substance affects genes, cells, tissues, organs, and organisms in causing disease. Students should acquire an understanding of the mechanisms of how disease is caused and the various areas and types of toxicologic research. Students should obtain an understanding of the basics of extrapolating from various types of toxicology research to questions of causation in humans that are at the heart of legal inquiries.
  5. An understanding of the legal issue of specific causation—whether the agent caused a given plaintiff’s disease. Students should obtain an understanding of how courts use, and sometimes misuse, epidemiologic outcomes as a way to answer specific causation questions. In addition, as genetic information increasingly is used to refine the specific causation question, student should gain an introductory understanding of how toxicogenomics and the use of biomarkers help address specific causation.  They should come to understand that currently the results of this area of science help to refine the probability of causation but rarely offer a clear answer to specific causation questions.

The module is designed for use in a classroom context with an instructor assisting students to absorb and understand the material in the module. A variety of slides designed to assist in this effort are included in the module along with study questions for class discussion. Extensive teaching notes guide the instructor and offer advice about how to present the material in class. The module contains descriptive material, figures and tables, abstracts and scientific studies, and legal opinions. A comprehensive hypothetical is provided for student assessment.

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