Table of Contents

Acknowledgments.

Foreword.

Preface.

Part I: Introduction.

1 The philosophy of evidence-based medicine.

1.1 What on earth was medicine based on before evidence-based medicine?

1.2 Scope of the book.

1.3 How the claims of EBM will be examined.

1.4 Structure of what is to come.

2 What is EBM?

2.1 EBM as a self-proclaimed Kuhnian paradigm.

2.2 The motivation for the birth of EBM: a sketch.

2.3 Original definition of EBM.

2.4 Reaction to criticism of the EBM system of evidence: more subtle, more or less the same.

3 What is good evidence for a clinical decision?

3.1 Introduction.

3.2 Evidence for clinical effectiveness.

3.3 Strong evidence tells us what?

Part II: Do randomization, double masking, and placebo controls rule out more confounding factors than their alternatives?

4 Ruling out plausible rival hypotheses and confounding factors: a method.

5 Resolving the paradox of effectiveness: when do observational studies offer the same degree of evidential support as randomized trials?

5.1 The paradox of effectiveness.

5.2 Observational studies: defi nition and problems.

5.3 Randomized trials to the rescue.

5.4 Defending the EBM view that randomized trials provide better evidence than observational studies.

5.5 Overcoming the paradox of effectiveness.

5.6 Conclusion: a more subtle way to distinguish between high- and low-quality comparative clinical studies.

Appendix 1: types of restricted randomization.

Appendix 2: Worrall’s arguments that randomization is required for classical hypothesis testing and establishing probabilistic causes.

6 Questioning double blinding as a universal methodological virtue of clinical trials: resolving the Philip's paradox.

6.1 The problems with double masking as a requirement for clinical trial validity.

6.2 The many faces of double masking: clarifying the terminology.

6.3 Confounders that arise from participant and caregiver knowledge.

6.4 The importance of successful double masking.

6.5 One (and a half) solutions to the Philip's paradox.

6.6 The full solution to the Philip's paradox: challenging the view that double masking rules out confounding factors when treatments are evidently dramatic.

6.7 Double masking is valuable unless the treatment effects are evidently dramatic, hence the Philip’s paradox does not arise.

7 Placebo controls: problematic and misleading baseline measures of effectiveness.

7.1 The need to control the placebo.

7.2 Legitimate placebo controls.

7.3 How placebo controls often violate the fi rst condition for legitimacy.

7.4 How placebo controls often violate the second condition for legitimacy.

7.5 Special problem for constructing placebos for complex treatments: case studies of exercise and acupuncture.

7.6 Summary and solution to the problem with illegitimate placebo controls.

8 Questioning the methodological superiority of "placebo" over "active" controlled trials.

8.1 Epistemological foundations of the ethical debate over the use of placebo-controlled trials.

8.2 Problems with the assay sensitivity arguments against ACTs.

8.3 Problems with the fi rst assay sensitivity argument against ACTs.

8.4 The second assay sensitivity argument.

8.5 Challenging the view that PCTs provide a measure of absolute effect size.

8.6 Questioning the claim that PCTs require smaller sample sizes.

8.7 Conclusion: a reassessment of the relative methodological quality of PCTs.

Appendix: more detailed explanation of why the second assay sensitivity argument fails.

Part III: Examining the paradox that traditional roles for mechanistic reasoning and expert judgment have been up-ended by EBM.

9 Transition to Part III.

9.1 Summary of Part II.

9.2 Introduction to Part III.

10 A qualifi ed defence of the EBM stance on mechanistic reasoning.

10.1 A tension between proponents of mechanistic reasoning and EBM views.

10.2 Clarifying the terminology: comparative clinical studies, mechanisms, and mechanistic reasoning.

10.3 Why the strong view that mechanistic reasoning is necessary to establish causal claims is mistaken.

10.4 Two epistemological problems with mechanistic reasoning.

10.5 Why EBM proponents should allow a more prominent role for high-quality (valid and based on "complete" mechanisms) mechanistic reasoning in their evidence hierarchies.

10.6 Mechanisms and other roles in clinical medicine.

10.7 Recommending a (slightly) more important role for mechanistic reasoning in the EBM system.

Appendix: cases where mechanistic reasoning led to the adoption of therapies that were either useless or harmful according to well-conducted clinical research.

11 Knowledge that versus knowledge how: situating the EBM position on expert clinical judgment.

11.1 Controversies surrounding the EBM stance on expert clinical judgement.

11.2 General clinical judgment belongs at the bottom of (or off) the hierarchy of evidence.

11.3 Individual clinical judgment also belongs at the bottom of the hierarchy.

11.4 The equally important non-evidential roles of expertise.

11.5 Conclusion.

Part IV: Conclusions.

12 Moving EBM forward.

12.1 Summary of fi ndings: the EBM philosophy is acceptable, but. . ..

12.2 Two new frontiers for EBM.

References.

Index.

About the Author

Jeremy Howick PhD Centre for Evidence-Based Medicine, Department of Primary Care,University of Oxford, UK

Reviews

Well-written, concise, engaging. The Evidence-basedmedicine (from now on 'EBM') movement continues to go from strengthto strength, with their hierarchy of medical evidence widely agreedupon and very influential in the theoretical and practical. ( The Guardian , 24 January 2014) Review appeared in TheGuardian - 24 January 2014 In conclusion, The Philosophy of Evidence-Based Medicine isa must-have as a source of knowledge of and reference to the EBMmovement. Howick presents the argument for EBM persuasively whilstgiving sufficient coverage to alternative positions. Ithoroughly recommend this text as both a 'way in' to the subjectand a source of deeper understanding in the latest stage ofmedicine's fascinating journey, full of twists and turns inthe search for the truth. ( Economics PHIlosophy , 1 January 2014) The book is well structured and makes an accessible andpleasant read. It deserves to be digested not only by philosopherswith a methodological bent but by practitioners of EBM. After twodecades of criticisms of various aspects of the increasinglypopular EBM way of reasoning, it is about time EBM defenders triedto strike back, clarifying and justifying their positions.Howick s book is a valuable effort that will hopefully enrichthe continuing debate. ( Theoria , 1 April2013) "Jeremy Howick has written the most comprehensive and fairphilosophical treatment of EBM to date. Howick understands that EBMis not, first and foremost, a philosophical position, and that itsvarious components (e.g., evidence hierarchies) are not primarilyphilosophical theses. Rather, they are attempts to improve theefficacy of medicine... The book approaches its topic with thetools of mainstream analytical philosophy of science." (Philosophyof Science, 2013) " The Philosophy of Evidence Based Medicine helps answerthe question of how to think about medicine so thatjudgement can be made. The book addresses key questions aboutmedical decision-making, such as: what role should mechanisticreasoning have in determining appropriate medicalcare? And, what weight, if any, should be givento expert opinions? This isn t a book abouthow doctors think. It is about how doctors ought tothink... The Philosophy of Evidence BasedMedicine is an extremely important andpractical book about evidence-based medicine, and I considerit to be one of the most important contemporary books on thesubject. I recommend it very highly." (The Medical Media Review,2012) "In The Philosophy of Evidence-Based Medicine , JeremyHowick, PhD offers by far the most fully formed defence to date ofthe epistemology of EBM... Well-written and as approachable as anywork in the philosophy of science might hope to be... Howick is tobe commended for his careful analysis of epistemic ramifications ofmany of the methodologies of clinical epidemiology." (Journal ofEvaluation in Clinical Practice, 2011) "Howick's book provides a good overview of EBM's defense of thehierarchy of evidence and an excellent reference list for readerswho want to know more about EBM and its critics." (Theory ofMedical Bioethics, 2011) "Since the 1990s, the practice of medicine has become dominated bya new methodological reasoning process - that of evidence-basedmedicine. This book unpacks the assumptions inherent in thismethodology, shedding light on its contributions and limitations topatient care. It addresses misconceptions about and criticisms ofEBM in a cogent manner and provides valuable insight into how thecurrent world of medicine is being shaped. (Doody's, 2011)