Introduction to critical appraisal

Evidence-based nursing (EBN) means using the best available evidence from research, along with patient preferences and clinical experience, when making nursing decisions.¹ Nurses are increasingly concerned about ensuring that care is research based, and EBN offers a strategy to help nurses achieve this goal by using 5 steps:

Step 1: reflecting on practice and identifying areas of uncertainty

Step 2: translating these areas of uncertainty into focused, searchable questions²

Step 3: searching the literature for studies that use appropriate designs to help answer the question^3–6

Step 4: critically appraising the research

Step 5: changing practice if the research suggests this is necessary.

Previous Notebooks in Evidence-Based Nursing that have described the process of EBN ^2–6 were written with busy clinical nurses in mind. The next series of Notebooks will explore step 4 in detail—how to assess whether research findings are valid and appropriate for clinical application.

The volume of healthcare literature has been described in graphic terms. Did you know, for example, that Medline has indexed more than 9 million citations in more than 4,000 journals since 1966?⁷ Clearly, no individual practitioner can read this volume of research; nor should they try, as only a small proportion of it is of good quality. The trick to keeping abreast of the latest research is to quickly filter the good from the bad. For example, staff of the evidence-based journals office recently calculated that of 136 journals read for 4 evidence-based journals (Evidence-Based Nursing, Evidence-Based Mental Health, Evidence-Based Medicine, and ACP Journal Club), an estimated 8% of 21 100 articles passed evidence-based methodologic filters (personal communication, A McKibbon, 20 Mar 2000).

Anyone who has designed or implemented a research study knows that it can be difficult to do well. Researchers, like …