The Doctors Guide to Critical Appraisal

237 Pages·2012·5.59 MB·English

by  Narinder Kaur Gosall

Dedicated to our son, Dilip, whose inquisitive nature reminds us that we should never stop asking
questions.

© 2012 PasTest Ltd
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All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any
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First edition 2006, Second edition 2009, Third edition 2012
ISBN: 1 905635 818
ISBN: 978 1 905635 818
eISBN: 978 1 908185 846
A catalogue record for this book is available from the British Library.
The information contained within this book was obtained by the authors from reliable sources. However, while every effort has been
made to ensure its accuracy, no responsibility for loss, damage or injury occasioned to any person acting or refraining from action as a
result of information contained herein can be accepted by the publisher or the authors.

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Text prepared by Carnegie Book Production, Lancaster
Printed and bound by CPI Group (UK) Ltd, Croydon, CR0 4YY
About the authors
Introduction to the third edition
Acknowledgements

SECTION A – EVIDENCE-BASED MEDICINE
Introducing critical appraisal
Formulating a question
Search strategies
The journal
Organisation of the article

SECTION B – APPRAISING THE METHODOLOGY
Overview of methodology
The clinical question
Introducing study designs
Observational descriptive studies
Observational analytical studies
Experimental studies
Other types of study
Research pathway
Populations and samples
Bias
Confounding factors
Restriction
Matching
Randomisation
Concealed allocation
The placebo effect
Blinding
Endpoints
Validity
Reliability

SECTION C – INTERPRETING RESULTS
Basic statistical terms
Epidemiological data
Intention-to-treat analysis
Risks and odds
Types of data
Measuring data
Data distributions
Describing categorical data
Describing normally distributed data
Describing non-normally distributed data
Inferring population results from samples
Comparing samples – the null hypothesis
Comparing samples – statistical tests
Non-inferiority and equivalence trials
Correlation and regression
Systematic reviews and meta-analyses
Heterogeneity and homogeneity
Publication bias
Interim analysis

SECTION D – USING CHECKLISTS
Introduction to checklists
Aetiological studies
Diagnostic or screening studies
Treatment studies
Prognostic studies
Economic studies
Qualitative research
Guidelines

SECTION E – APPLICABILITY
The hierarchy of evidence
Critical thinking

SECTION F – CRITICAL APPRAISAL IN PRACTICE
Health information resources
Presenting at a journal club
Taking part in an audit meeting
Working with pharmaceutical representatives

Further reading
Answers to self-assessment exercises
A final thought
Index
Dr Narinder Kaur Gosall BSc (Hons) PhD
Director, Superego Cafe Limited
Narinder Gosall studied in Liverpool and gained a PhD in neuropathology after investigating the role
of the phrenic nerve in sudden infant death syndrome and intrauterine growth retardation. After
working as a university lecturer she joined the pharmaceutical industry. She worked in a variety of
roles, including as a Medical Liaison Executive and as a Clinical Effectiveness Consultant for Pfizer
Limited. She has extensive experience in teaching critical appraisal skills to healthcare professionals
and is an international speaker on the subject. She is the editor of the online course at
www.criticalappraisal.com.

Dr Gurpal Singh Gosall MA MB BChir MRCPsych
Consultant General Adult Psychiatrist, Lancashire Care NHS
Foundation Trust
Director, Superego Cafe Limited
Gurpal Gosall studied medicine at the University of Cambridge and Guy’s and St Thomas’s
Hospitals, London. He worked as a Senior House Officer in Psychiatry in Leeds before taking up a
post as Specialist Registrar in the North West. He now works as a Consultant Psychiatrist, looking
after patients in the Psychiatric Intensive Care Units at the Royal Blackburn Hospital and Burnley
General Hospital. He has a long-standing interest in teaching and runs a popular website for
psychiatrists, Superego Cafe, at www.superego-cafe.com.
Learning the skill of critical appraisal is like learning a foreign language – wherever you start, you
come across unfamiliar words and concepts. However, persistence pays off and, like speaking a
foreign language, the earlier it is mastered and the more it is used, the easier critical appraisal
becomes.

Critical appraisal skills are now as much a part of the clinician’s armoury as the ability to diagnose
conditions and prescribe treatments. Critical appraisal skills allow clinicians to prioritise evidence
that can improve outcomes. Such is the importance of acquiring these skills that critical appraisal is
now routinely tested in medical, dental and nursing exams.

We wrote the first edition of this book 6 years ago to explain critical appraisal to the busy clinician.
Our aim has always been for the book to be the one-stop solution for all clinicians. Based on our
teaching experience, we took a unique back-to-basics approach that provided a logical and
comprehensive review of the subject. This new edition expands on the last edition with updated
information, new chapters and more help with difficult topics.

We hope that by reading this book you will start reading and appraising clinical papers with more
confidence. The language of evidence-based medicine is not as foreign as you might think.

NKG, GSG

2012