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NSG607: Evidence-Based Practice: APPRAISE: Critical Appraisal

Course Guide for NSG607

Importance of Appraisal

Once you figure out what to look for and where, you'll still have to worry about the quality of the material you find. A poorly done systematic review is not better than a well done randomized controlled trial. On this page, you will find resources to help you with appraising the material you find.

Which articles are the "best"

stack of booksYou have your question, and you've got a great search strategy, but how do you know which articles are the "best"?

That depends on the type of information you are looking for:

  • Primary Sources: first hand evidence concerning a topic under investigation
  • Randomized controlled trials, cohort studies, case series, etc.

   Secondary Sources: summaries and analyses of the evidence derived from and based on primary sources

  •     Systematic Reviews/Meta-analyses, Qualitative Reviews, Practice Guidelines, etc. 

Evidence

  Critical appraisal is a systematic process of analyzing research to assess methods, validity and usefulness. 

 

The key questions in critical appraisal are:

Why was the study done?

  • A clearly focused question should address population, intervention and outcomes.

What type of study was done?

  • The study design must match the question asked. Intervention questions are best answered with randomized controlled trials.

What are the study characteristics?

  • Use the PICO question format to help you answer the question. 

What was done to address bias?

  • Was the assignment of patients to treatments randomized?
  • Were patients, health workers and study personnel ‘blind’ to treatment allocation? 
  • Were all of the patients who entered the trial properly accounted for at its conclusion? Look for follow-up tables and whether patients were analyzed in the groups to which they were randomized. 
  • Were the groups similar at the start of the study?
  • Aside from the experimental intervention, were the groups treated equally?

What are the results and are the results valid?

  • Are the outcome measures relevant?
  • How large was the treatment effect? How precise was the estimate of the treatment effect?
  • Look for confidence limits and p values.

What conclusions can you make?

  • Are the results generalizable, that is, can the results be applied to my patients?  Were all clinically important outcomes considered? Are the benefits worth the harms and costs?
  • Are the results relevant to my situation? Patient population / similar definitions/protocols/health system similarities.

Adapted from: Voutier, C. (2013). Critical appraisal. Evidence Direct: A Service of the RMH Health Sciences Library. Retrieved 17 December 2015 from: http://library.mh.org.au/index.php?option=com_content&view=article&id=272&Itemid=537