Читать книгу The Pocket Guide to Critical Appraisal - Iain K. Crombie - Страница 7

Several developments have highlighted the need for a second edition of this book. Recent work, particularly from the new discipline of meta‐research, has provided important evidence for critical appraisal. By examining and comparing large numbers of studies, this research has clarified the nature of and impact of many sources of bias. A separate development is the recognition that critical appraisal should distinguish between the risk of bias and the value of the findings to individuals, health care systems, and the wider society. Critical appraisal checklists should provide separate sets of questions for the two issues. Finally, many years of teaching critical appraisal skills have provided the author with an understanding of the difficulties that students and health professionals encounter when evaluating papers. These developments have led to improvements in the guidance given in this book.

This new edition follows the format and the spirit of the first: it is written to be easy to use and, where possible, technical terms are avoided. However, substantial modifications have been made. A new Introduction clarifies the aims of critical appraisal. The second chapter, entitled ‘Do Not Read the Paper’, is also new; it provides a simple method for eliciting the information needed for critical appraisal from published studies. This is supported by Chapter 5, ‘The In‐Depth Interrogation’, which is a much‐amended version of the original ‘Standard Appraisal Questions’. In addition, Chapter 4 on ‘Interpreting the Results’ has been updated in line with current views on the nature of statistical significance and the interpretation of confidence intervals.

All of the chapters that provide checklists for critical appraisal of specific research designs have been revised and updated, particularly Chapter 9, ‘Appraising Randomised Controlled Trials’, and Chapter 11, ‘Appraising Systematic Reviews’. A new chapter for the critical appraisal of cohort studies that evaluate interventions has been added. This research design is now being frequently used in medical research (the separate chapter on conventional cohort studies has been retained). All the checklists distinguish between critical and important sources of bias and they evaluate risk of bias separately from value.

Two new chapters at the end of the book provide methods for synthesising the findings of critical appraisal. One provides a method for summarising risk of bias. The second explores the important concept of certainty of evidence and describes how it is assessed. A further new chapter reviews the wide range of factors that determine the value of research findings to society as a whole. This second edition provides a much‐needed update to the guidance on critical appraisal.