Evidence-Based Medicine: Determining Quality of Randomized Controlled Trials
Melissa Cheng
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Abstract

Evidence-based medicine is based on evidence gathered by randomized controlled trials (RCTs), which are considered the “gold standard” of research studies. Users of the medial literature must be able to read critically and evaluate RCTs. The present article uses the standards of the American College of Occupational and Environmental Medicine (ACOEM) practice guidelines in evaluating RCTs according to 11 criteria; these criteria follow those used by the Cochrane Collaboration in their evidence-based reviews. Well-written articles present their randomization schemes to create comparable groups, and studies must be controlled for co-interventions; in a double-blind trial, the co-interventions would be used equally in both groups, and treatment allocations should be concealed. Readers should ask if the study had acceptable compliance; that is, were patients doing what they were asked, and was the dropout rate acceptable (typically, less than 20%)? RCTs should be analyzed by an intention-to-treat analysis that includes all study subjects who were randomized, not just those who completed the study. Having high internal validity ensures a more accurate study that can be reproduced by others, so readers may ask if results are likely to be affected by observational bias, confounding, or chance variation. Readers can determine external validity by assessing study participants according to inclusion and exclusion criteria and baseline characteristics.

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