Common Biases in Critical Appraisal of the Literature

A list of the common biases encountered in critical appraisal of the medical literature.

Scientific Biases

Selection Bias

• • an unequal distribution of potential confounders between groups in a controlled trial as a result of non-random allocation

  • http://www.ebm.med.ualberta.ca/Glossary.html#Selectionbias

Cognitive Biases

Confirmation Bias

• • a tendency to look for/pay attention to evidence that merely confirms the position you already hold, rather than looking for refuting evidence

  • http://www.psnet.ahrq.gov/glossary.aspx#confirmationbias