Appraising the evidence
Almost all scientific studies are flawed and it would come as a surprise to some clinicians that some (perhaps most) published papers (ref 1) should be thrown in the bin rather than used to inform clinical practice.
The important thing is not to stop questioning. Curiosity has its own reason for existing. Albert Einstein 1879-1955
Critical appraisal is a way of rapidly assessing published papers in order to sort out the relevant or valid papers from the poor quality or irrelevent ones.
Validity - is the degree to which the results of the study are likely to be true, believable and free from bias.
Bias - is any factor (other than the experimental factor) that could change the study results in a non-random way.
Critical appraisal is best carried out in a structured/standardised way using explicit criteria. Appraisal can help the clinician to assess:
- Validity
- Clinical importance
- Clinical relevance
A number of appraisal worksheets are available in the resources section.
1. Altman D. The scandal of poor medical research. (Editorial) BMJ 1994; 308: 283-284.
Page last edited: 09 December 2007
