Critical appraisal

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See also Critical thinking | Journal clubs | Evidence-based health care | Research Portal for Academic Librarians | Scholarship 2.0

"...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) What is critical appraisal?

Critical appraisal refers to the process of carefully and systematically examining published research in order to judge its value and relevance in particular contexts. More specifically, critical appraisal of a study or article is more than simply reading it; it is a technique that aims to improve your ability to read research and assess its quality. Further it is the use of an explicit method or methods to evaluate research particularly studies and clinical trials in journals. The process of critical appraisal involves the application of rules around matters of internal validity, reporting standards, conclusions and generalizability of the research in question. Critical appraisal is a central tenet in the systematic review and used in evidence-based health care to assist in making decisions. Moreover, critical appraisal is an important lifelong learning skill when reading the research and requires some knowledge of qualitative information and its validity/ generalizability. In reading the research, whether more rigorous systematic reviews, randomized controlled trials (RCTs), economic evaluations or other, remember to consider the following questions: 1) Is external or internal validity demonstrated? 2) How has the study obtained its results? and 3) What is the study's relevance to research to practice (or within the context of knowledge synthesis in medicine).

Critical appraisal questions

Consider the following questions as you assess the research :

  1. Has the research been done on a patient sample before? What size? How was data collected?
  2. Was research conducted to minimize bias? (What is bias?)
  3. What does the study tell us? Are the results applicable to other contexts?
  4. What do the results mean for specific patients where decisions must be made?

The skills of critical appraisal are absolutely essential in an era of evidence-based health care:

  • Research questions typically require appropriate study designs; the best study design for testing medical interventions is the randomized controlled trial (RCT)
  • Information science (and health librarianship) generates some RCTs (and systematic reviews) but in small quantities
  • Some studies are subject to bias; we must take steps to minimize bias by control groups, randomization techniques and blinding
  • Does the study add anything new to the body of literature? Was a literature review conducted? Are methods explicit?
  • Systematic reviews, which collect, appraise and combine evidence, are useful at pooling studies to determine overall impact see Meta-analysis

Towards EBLIP in health librarianship

Critical appraisal is an essential skill for evidence-based library and information practice (EBLIP) for it allows librarians to find and use research evidence reliably and efficiently. However, librarians do not always have ease of access to best evidence in their field. In order to make decisions about information practices, health librarians also need to develop their critical appraisal skills beyond those that are discussed by proponents of EBLIP. Research involves gathering, collating and analyzing data to identify patterns and trends. However, not all research has been conducted using reliable methods and some studies are biased. This can lead to false conclusions; how can we tell whether research has been done properly and that the information it reports is reliable and trustworthy? How can we trust research when it comes to conclusions that contradict previous research? This is where critical appraisal is indispensable as we read the library and information science (LIS) literature.

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Appraisal guides and tools


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