The Philosophy of Evidence-based Medicine

The Evidence-based medicine (from now on 'EBM') movement continues to go from strength to strength, with their hierarchy of medical evidence widely agreed upon and very influential in the theoretical and practical aspects of medicine. Howick's very tidy manuscript argues forcefully, but fairly, for EBM and surveys many of the topics that will be of interest to readers whether philosophers of science, or more specifically philosophers of medicine or medical practitioners themselves keen to appreciate the theoretical underpinnings of their work.The introduction provides a neat, concise historical explanation for the origins and prominence for EBM, with a specific focus on the EMB hierarchy of evidence and the reception to such evidence. Broadly speaking, the hierarchy places randomised controlled trials (commonly known as RCTs) above observational studies, which itself is above expert judgement. Howick's clear diagram makes this claim straightforward and prepares the reader for the remainder of the book which can be seen as, one way or another, dissecting this hierarchy.Part II critically evaluates the top half of the EBM hierarchy pyramid: do RCTs produce better evidence than observational studies? Chapter 5, on the paradox of effectiveness (our best therapies like the Heimlich manoeuvre do not have so-called best, RCT, evidence) is not only an intriguing thought, but the entire chapter is brilliantly written, illustrating the confounders arising from selection and performance bias that observational studies are plagued by whereas RCTs, via double-masking and randomisation, can eliminate these confounders (alternative explanations for the effect size of the intervention). Howick has a rare ability of writing in very terse prose but capturing enough information for sufficient understanding. This remains the style throughout. As a result, The Philosophy of Evidence-Based Medicine is very easy to read, and can be mastered in a short space of time.Part III is dedicated to looking at the bottom of the EBM evidence hierarchy, namely expert judgement. Howick himself applies expert judgement in summarising the first two parts at the beginning of this section. In fact, this is a tool used throughout. The author recognises the lack of formal background some readers will have on opening the text, and thus summaries can be found in many key paragraphs as well as big sections, signposted by 'in sum'. This part moves away from the strict comparisons of experiments towards the epistemological aspects of medicine, in particularly a challenging chapter on how mechanistic reasoning functions, a topic that can be well applied to issues of causality well beyond philosophy of medicine.In conclusion, The Philosophy of Evidence-Based Medicine is a must-have as a source of knowledge of and reference to the EBM movement. Howick presents the argument for EBM persuasively whilst giving sufficient coverage to alternative positions. I thoroughly recommend this text as both a 'way in' to the subject and a source of deeper understanding in the latest stage of medicine's fascinating journey, full of twists and turns in the search for the truth.