Physical Therapist Assistant

Critical appraisal is the process of carefully and systematically examining research to judge its trustworthiness, its value, and its relevance in a particular context.

Information, calculators, checklists, and tools to help you critically appraise research articles are provided on this page.

These tools will help you to interpret the clinical and statistical significance of data reported in clinical research.

When appraising research, keep the following three criteria in mind:

Quality 
Trials that are randomised and double blind, to avoid selection and observer bias, and where we know what happened to most of the subjects in the trial.

Validity
Trials that mimic clinical practice, or could be used in clinical practice, and with outcomes that make sense. For instance, in chronic disorders we want long-term, not short-term trials. We are [also] ... interested in outcomes that are large, useful, and statistically very significant (p < 0.01, a 1 in 100 chance of being wrong).

Size
Trials (or collections of trials) that have large numbers of patients, to avoid being wrong because of the random play of chance. For instance, to be sure that a number needed to treat (NNT) of 2.5 is really between 2 and 3, we need results from about 500 patients. If that NNT is above 5, we need data from thousands of patients.

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

Source:  Critical Appraisal. Bandolier.

Did you know that you can check out a copy of Trisha Greenhalgh's How to Read a Paper at the MEC Library?

How to Read a Paper: The Basics of Evidence-based Medicine