Library resources for the School of Nursing


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

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

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).

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.

How To Read a Paper

Dr. Trisha Greenhalgh's clearly written papers (full-text links to each below) discuss how to critically appraise the medical literature. These articles appeared originally in the British Journal of Medicine and were later produced as a book:  How to Read a Paper.

Tutorial for EB Nursing

Evidence-Based Nursing:  an Evidence-Based Nursing Tutorial from the Information Services Department of the Library of the Health Sciences-Chicago, University of Illinois at Chicago.