The Pyramid Schema: The Origins and Impact of Evidence Pyramids

[This paper has been updated in 2026 from the 2022 preprint] Evidence pyramids are amongst the most recognisable artefacts of the Evidence-Based Medicine movement. Yet no study has established the origins of evidence pyramids, or analysed whether they offer any information beyond simple lists or tables. In this paper, I establish the origins of the first evidence pyramid and argue that the pyramidal turn is a retrograde step in evidence appraisal.

The Machine Scientists: Iatrophysics and Selective Scientific Realism

The Machine Scientists – Giovanni Borelli, Jan Swammerdam and Niels Steensen – followed Rene Descartes in modelling the human body mechanically. The scientific success of this ‘iatrophysical’ programme, replete with rejected entities such as ‘Animal Spirits’, poses a problem for Scientific Realism. Using Psillos’ moderate realism, this paper attempts to reconcile a selective realist position with the historical record.

Random Reflections: Cochrane and the Origins of Hierarchies

In 1972, Archie Cochrane published Effectiveness and Efficiency: Random Reflections on Health Services. In a little under 86 pages, Cochrane offers a wide-ranged but succinct delivery of his experience and his philosophy of evidence in clinical practice. It’s a fascinating gallop through the concerns of one of the most influential figures …

A Ghost of Progress – How Hierarchies Become Fixtures

I have written extensively on hierarchies of evidence in evidence-based medicine. The origin story of hierarchies of evidence is a little contentious. Several sources in EBM cite Campbell and Stanley’s 1963 classic “Experimental and Quasi-experimental Designs for Research” as containing the first hierarchy, or at least the germ of the …