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Evidence Based Practice (NUR 4169)

What is Critical Appraisal?

"Critical appraisal is the process of carefully and systematically examining a research report to judge its trustworthiness, make sense of the results and assess the relevance of the findings in a particular context."

Burls, Amanda. (2015) "What is Critical Appraisal?" What is...? series. Hayward Medical Communications. Retrieved from

OR in other words...

Critical Appraisal is the process of systematically evaluating scientific research/evidence in order to judge validity, relevance and value within a particular context.  This is a necessary tool. for life-long learning and should be used every time you read a primary study.

-- retrieved from: Critical Appraisal Institute through the New York Medical College

Critical Appraisal Worksheets

Once you have located published evidence, it's time to critically appraise those studies. Critical appraisal worksheets pose a structured series of questions that can help you assess study methodology, validity, and applicability to your clinical question. Here are some good ones to check out:

An Introduction...

The Four Possibilities...

There are 4 possible explanations for every study finding. It is your job when you read a study to figure out the role each of these plays. Please consider these 4 things for every study you evaluate.

  1. Truth:  The finding is real. Truth can only be determined by studying every person with a disease or condition.  Studies are completed to ESTIMATE truth.
  2. Chance:  Random error.  Assessed by hypothesis testing and estimation.
  3. Bias:  Systematic (or non-random) errors in study design or conduct that lead to over or under estimation of effect. When you critically appraise an article you are looking for bias.
  4. Confounding:  A 3rd factor outside of the causal chain that influences the effect on cause & outcome.

-- retrieved from: Critical Appraisal Institute through the New York Medical College