Richard Woltereck first described the concept of Reaktionsnorm (norm of reaction) in his 1909 paper "Weitere experimentelle Untersuchungen über Art-veränderung, speziell über das Wesen quantitativer Artunterschiede bei Daphniden" (Further investigations of type variation, specifically concerning the nature of quantitative differences between varieties of Daphnia).
In 1965, Austin Bradford Hill published the article "The Environment and Disease: Association or Causation?" in the Proceedings of the Royal Society of Medicine. In the article, Hill describes nine criteria to determine if an environmental factor, especially a condition or hazard in a work environment, causes an illness. The article arose from an
During the twentieth century, Austin Bradford Hill researched diseases and their causes in England and developed the Bradford Hill criteria, which comprise the minimal requirements that must be met for a causal relationship to be established between a factor and a disease. Hill also suggested that researchers should randomize clinical trials to evaluate the effects of a drug or treatment by monitoring large groups