Causality, mathematical models and statistical association: dismantling evidence-based medicine


  • R. Paul Thompson BA MA PhD

    1. Professor, Institute for the History and Philosophy of Science, and Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
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Professor R. Paul Thompson
Institute for the History and Philosophy of Science and Technology
Victoria College
University of Toronto
91 Charles Street West
Toronto, ON
Canada M5S 1K7


From humble beginnings, largely at the medical school at McMaster University, Canada, the evidence-based medicine (EBM) movement has enjoyed a spectacular rise in international acceptance over the last 25 years. Randomized controlled trials (RCTs) and systematic reviews based on them have pride of place (the gold standard) in EBM's hierarchy of evidence; models and theories are relegated to the bottom of the hierarchy. In the last decade, RCTs have been extensively criticized. I briefly rehearse those criticisms because they are an important backdrop to the criticism of EBM developed in this paper. In essence, the argument developed here is that RCTs use mathematics solely as a tool of analysis rather than as the language of the science and that this fundamentally affects the validity of causal claims. As EBM gives pride of place to RCTs and devalues theoretical models – a devaluation that would be incomprehensible to a physicist or biologist – the validity of EBM's causal claims and knowledge claims are weak and far from a ‘gold standard’.