Summary and Introduction
Critical appraisal is a systematic process used to identify the strengths and weaknesses of a research article in order to assess the usefulness and validity of research findings. The most important components of a critical appraisal are an evaluation of the appropriateness of the study design for the research question and a careful assessment of the key methodological features of this design. Other factors that also should be considered include the suitability of the statistical methods used and their subsequent interpretation, potential conflicts of interest and the relevance of the research to one's own practice. This Review presents a 10-step guide to critical appraisal that aims to assist clinicians to identify the most relevant high-quality studies available to guide their clinical practice.
To practice evidence-based medicine, clinicians need to apply the findings of scientific research to the circumstances of individual patients as part of their clinical decision-making process. Clinicians, therefore, must be able to select and appraise scientific literature that is relevant to their field, understand the implications of research findings for individual patients, elicit patients' own preferences and develop an appropriate management plan based on the combination of this information. Each of these tasks presents its own challenges, but the sheer volume of medical literature means that the first step (that of selecting and appraising scientific evidence) can be daunting. The number of new medical research articles published each year continually increases, and more than 12,000 new articles, including papers on in excess of 300 randomized controlled trials (RCTs), are added to the MEDLINE database each week.[1,2] One practical way that clinicians can manage this 'information overload' is to develop efficient skills in critical appraisal, which enable them focus on only the highest-quality studies that will guide their clinical practice and to extrapolate information when necessary from studies of less rigorous design if high-quality trials are unavailable.
Critical appraisal has been defined as the "...application of rules of evidence to a study to assess the validity of the data, completeness of reporting, methods and procedures, conclusions, compliance with ethical standards, etc. The rules of evidence vary with circumstances." Although the methodological criteria by which the validity of a study is assessed will vary according to its design, some general principles underpin the evaluation of any research study. Various guidelines and assessment tools have been developed to provide a structured approach to the process of critical appraisal for clinicians.[4,5,6,7,8,9,10,11,12,13,14]
Despite the plethora of documents available to guide the process, no 'gold-standard' instrument for critical appraisal exists. The criteria used to assess the validity and relevance of scientific literature are not static; they must evolve with improvements in understanding of the important sources of bias inherent in different study designs, and increased awareness of the potential influence of other nonmethodological factors, such as conflicts of interest. A structured approach to critical appraisal could potentially improve the quality of this process, and simple checklists can be useful to screen out research that is of low quality or of little relevance. This Review presents a guide to the critical-appraisal process.
Nat Clin Pract Gastroenterol Hepatol. 2009;6(2):82-91. © 2009 Nature Publishing Group
Cite this: How to Critically Appraise an Article - Medscape - Feb 01, 2009.