Fourth Edition
This fourth edition first published 2018
© 2018 by John Wiley & Sons Ltd
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Library of Congress Cataloging‐in‐Publication Data
Names: Machin, David, 1939– author. | Campbell, Michael J., 1950– author. | Tan, Say Beng, author. | Tan, Sze Huey, author.
Title: Sample Sizes for Clinical, Laboratory and Epidemiology Studies / David Machin, Michael J. Campbell, Say Beng Tan, Sze Huey Tan.
Description: Fourth edition. | Hoboken, NJ : Wiley, [2018]. | Preceded by Sample size tables for clinical studies / David Machin ... [et al.]. 3rd ed. 2009. | Includes bibliographical references and index. |
Identifiers: LCCN 2018001008 (print) | LCCN 2018002299 (ebook) | ISBN 9781118874929 (pdf) | ISBN 9781118874936 (epub) | ISBN 9781118874943 (hardback)
Subjects: | MESH: Research Design | Clinical Studies as Topic | Statistics as Topic | Sample Size | Tables
Classification: LCC R853.C55 (ebook) | LCC R853.C55 (print) | NLM W 20.55.C5 | DDC 615.5072/4–dc23
LC record available at https://lccn.loc.gov/2018001008
Cover design: Wiley
Cover images: © Ralf Hiemisch / Getty Images (Background Abstract Image) © SergeyIT / Getty Images (Crowd Image on Top), © SUWIT NGAOKAEW / Shutterstock (Scientist Image on bottom)
It has been more than thirty years since the original edition of ‘Statistical Tables for the Design of Clinical trials’ was published. During this time, there have been considerable advances in the field of medical research, including the completion of the Human Genome Project, the growth of personalised (or precision) medicine using targeted therapies, and increasingly complex clinical trial designs.
However, the principles of good research planning and practice remain as relevant today as they did thirty years ago. Indeed, all these advances in research would not have been possible without investigators holding firm to these principles, including the need for a rigorous study design and the appropriate choice of sample size for the study.
This fourth edition of the book features a third change in title. The original title had suggested (although not intentionally) a focus on ‘clinical trials’, the second saw an extension to ‘clinical studies’ and now ‘clinical, laboratory and epidemiology studies’. Currently, sample size considerations are deeply imbedded in planning clinical trials and epidemiological studies but less so in other aspects of medical research. The change to the title is intended to draw more attention to areas where sample size issues are often overlooked.
This text cannot claim to be totally comprehensive and so choices had to be made as to what to include. In general terms, there has been a major reorganisation and extension of many of the chapters of the third edition, as well as new chapters, and many illustrative examples refreshed and others added. In particular, basic design considerations have been extended to two chapters; repeated measures, more than two groups and cluster designs each have their own chapter with the latter extended to include stepped wedge designs. Also there is a chapter concerning genomic targets and one concerned with pilot and feasibility studies.
In parallel to the increase in the extent of medical research, there has also been a rapid and extensive improvement in capability and access to information technology. Thus while the first edition of this book simply provided extensive tabulations on paper, the second edition provided some basic software on a floppy disc to allow readers to extend the applicability to situations outside the scope of the printed tables. This ability was further enhanced in the third edition with more user‐friendly and powerful software on a CD‐ROM provided with the book. The book is supported by user‐friendly software through the associated Wiley website. In addition, R statistical software code is provided.
Despite these improved software developments, we have still included some printed tables within the text itself as we wish to emphasise that determining the appropriate sample size for a study is not simply a task of plugging some numerical values into a formula with the parameters concerned, but an extensive investigation of what is suitable for the study intended. This would include face‐to‐face discussions between the investigators and statistical team members, for which having printed tables available can be helpful. The tabulations give a very quick ‘feel’ as to how sensitive sample sizes can often be to even small perturbations in the assumed planning values of some of the parameters concerned. This brings an immediate sense of realism to the processes involved.
For the general reader Chapters 1 and 2 give an overview of design considerations appropriate to sample size calculations. Thereafter the subsequent chapters are designed to be as self‐contained as possible. However, some later chapters, such as those describing cluster and stepped wedge designs, will require sample size formulae from the earlier chapters to complete the sample size calculations.
We continue to be grateful to many colleagues and collaborators who have contributed directly or indirectly to this book over the years. We specifically thank Tai Bee Choo for help with the section on competing risks, Gao Fei on cluster trials and Karla Hemming and Gianluca Baio on aspects of stepped wedge designs.
The authors would like to dedicate this book to Oliver, Joshua, Sophie and Caitlin; Matthew, Annabel, Robyn, Flora and Chloe; Lisa, Sophie, Samantha and Emma; Kim San, Geok Yan and Janet.