Chapter 11: Chance

Introduction Learning from clinical experience, whether during formal research or in the course of patient care, is impeded by two processes: bias and chance. As discussed in Chapter 1, bias is systematic error, the result of any process that causes observations to differ systematically from the true values. Much of this book has been about […]

Chapter 12: Cause

Introduction This book has been about three kinds of clinically useful information. One is description, a simple statement of how often things occur, summarized by metrics such as incidence and prevalence, as well as (in the case of diagnostic test performance) sensitivity, specificity, predictive value, and likelihood ratio. Another is prediction, evidence that certain outcomes […]

Chapter 13: Summarizing the Evidence

Introduction Clinical decisions are based on the weight of evidence bearing on a question. Sometimes the results of large, strong studies are so compelling that they eclipse all other studies of the same question. More often, however, clinicians depend on the accumulation of evidence from many less definitive studies. When considering these individual studies, clinicians […]

Chapter 14: Knowledge Management

Introduction Finding the best available answer to a specific clinical question is like finding a needle in a haystack. Essential information is mixed with a vast amount of less credible “factoids” and opinions, and it is a daunting task to sort the wheat from the chaff. Yet, that is what clinicians need to do. Critical […]

Appendix: Answers to Review Questions

Chapter 1 Introduction 1.1. D. Samples can give a misleading impression of the situation in the parent population, especially if the sample is small. 1.2. E. Generalizing the results of a study of men to the care of a woman assumes that the effectiveness of surgery for low back pain is the same for men […]