What is critical appraisal?

Critical appraisal involves critically examining a study to determine its validity, reliability and relevance. It is an important and essential part of the EBP 5 step process. For a more comprehensive overview refer to the critical appraisal for health guide.

It is useful to ask the following three questions when conducting an appraisal:

  1. Are the results of the study valid?
  2. Are the results of the study reliable?
  3. Are the results applicable to my situation? (Saewert & Hagler, 20151).

There are many different appraisal tools that can be used depending on the type of study. See below for some examples.

 1.  Saewert, K. J., & Hagler, D. (2015). Generating the evidence for health professional education: The five As of the scholarship of learning and teaching - ask, answer, access, appraise and apply. In T. Brown & B. Williams (Eds.), Evidence-based education in the health professions: Promoting best practice in the learning and teaching of students (pp. 67-80). London: Radcliffe.

Critical appraisal tools & guides

There are a number of checklists / tools available Internet to assist in the critical appraisal of evidence.

Key EBP statistics

The probability that a particular result could have happened by chance. Used to assess whether results are statistically significant (where the P-value is less than 5% - P<0.05).

P-values and Type I Error by Terry Shaneyfelt (YouTube)

An estimate of treatment effect which accounts for the sampling error between the study population and the larger population that the study represents. Indicates that in the wider population, there is e.g. 95% confidence that results would fall within a given range. A narrow range indicates a higher degree of precision.

Confidence Intervals by Terry Shaneyfelt (YouTube)

A measure of the effectiveness of interventions which indicates clinical significance. The number of patients who need to be treated to prevent one bad outcome.

Recommended resources