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Critical Appraisal

This guide describes tools to critically evaluate evidenced based reviews and study designs

What is Critical Appraisal?

Critical appraisal is the process of carefully and systematically examining research to judge its trustworthiness,
and its value and relevance in a particular context. (Burls 2009)

Critical appraisal is an important element of evidence-based medicine. The five steps of evidence-based
medicine are:

  1. asking answerable questions, i.e. formulating questions into a format whereby you can interrogate themedical literature and hopefully find an answer - to do this, you may use the PICO tool, which helps to break down the query into Population, Intervention, Comparison, Outcome;
  2. you then need to search for the evidence - if you can find a pre-appraised resource, you can miss out  the next step
  3. the next step is critical appraisal of your results;
  4. you then decide what action to take from your findings;
  5.  finally, you evaluate your new or amended practice

Critical appraisal is essential to:

  • combat information overload;
  • identify papers that are clinically relevant;
  • Continuing Professional Development (CPD) - critical appraisal is a requirement for the evidence based medicine component of many membership exams.

What to consider when getting started with a systematic review

Time - An average systematic review requires about 18 months of preparation.

Team - Subject experts to help clarify issues related to the topic; librarians who can develop the comprehensive search strategies and identify the appropriate databases to search; reviewers who can screen abstracts and read the full text; statistician who can assist with the appropriate analysis of the data; and project leader who will coordinate and write the final report

Written protocol - A written protocol outlines the methodology, including the rationale for the systematic review, key questions broken into PICO components, inclusion/exclusion criteria, and literature search for both published and unpublished literature, data abstraction and data management, assessment of methodological quality of individual studies, data synthesis, and grading the evidence for each key question.

Literature searching - First, identify systematic reviews that may already address the key questions; then identify the appropriate databases and conduct a comprehensive and detailed literature search that can be documented and duplicated.

Citation management - Gain a working knowledge of EndNote or other software package to help manage the citations from the literature search.

Guidelines for reporting - Use the appropriate guidelines for reporting your review for publication.