Sir Austin Bradford Hill presents the paper "The Environment and Disease: Association or Causation" at the Royal Society of Medicine in London.
"... Hill suggests nine factors to be considered in determining whether a statistical association in a population between exposure to some substance and incidence of some disease or disorder is indicative of causation ..."
-- Quoted material from "Evidence Matters: Science, Proof and Truth in the Law" (Susan Haack, 2014): @
-- Chart from "Textbook of Cancer Epidemiology" (2008): @
* PDF of paper: @
* Summary (from Science-Based Medicine): @