Understanding Commonly Encountered Limitations in Clinical Research: An Emergency Medicine Resident's Perspective

Abstract

The breadth of emergency medicine and the rapid growth in relevant research makes an ability to assess new research findings particularly important for emergency physicians. Improvements in the treatment of acute myocardial infarction, evolution of thrombolytic use in acute stroke, and the demise of military antishock trousers for traumatic shock provide examples of the dynamic relationship between emergency medicine research and clinical practice. The purpose of this article is to provide an overview of common research limitations and flaws relevant to emergency medicine. We explain and provide published examples of problems related to external validity, experimenter bias, publication bias, straw man comparisons, incorporation bias, randomization, composite outcomes, clinical importance versus statistical significance, and disease-oriented versus patient-oriented outcomes. For residents, familiarity with these concepts will allow for better interpretation of evidence-based lectures and improved understanding and participation during journal clubs. For those who learn best from review articles, textbooks, or other summaries of primary literature, awareness of these issues is needed to understand critiques raised by reviewers. For all readers, knowledge of these commonly encountered methodological problems will improve the emergency provider’s ability to determine whether and how new scientific developments serve to inform clinical practice. By necessity, this article is only a starting point for learning about these subjects, many of which are complex. Readers are encouraged to refer to questions and answers from the Annals of Emergency Medicine Journal Club series. Available topics from this series are described in Appendix E1, available online at http://www.annemergmed.com.