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Critical appraisal


The process of assessing and interpreting evidence by systematically considering its validity, results and relevance.

Bandolier has available a longer essay on critical appraisal - What is critical appraisal?

This sounds great, and often is. Of course, one needs to look at different forms of evidence differently - controlled trials, versus observational studies, for instance. Or diagnostic studies, or health economic studies. A number of schema have been developed for doing this, and are useful. The trouble is that any one of them can be wrong for a given paper, because some things are hard to define, like what constitutes a valid or relevant study.

The three things to bear in mind are quality, validity, and size:

These are the criteria on which we should judge evidence. For it to be strong evidence, it has to fulfil the requirements of all three criteria.