Evidence-Based Medicine: Determining Quality of Randomized Controlled Trials
Melissa Cheng
Search for other papers by Melissa Cheng in
Current site
Google Scholar
Restricted access


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.

  • 1.

    Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson WS. Evidence based medicine: what it is and what it isn't. BMJ. 1996;312(7023):71-72.

    • Search Google Scholar
    • Export Citation
  • 2.

    Harris J, Sinnott P, Turkelson C, Weiss M, Hegmann KT. Methodology to Update the Practice Recommendations in the American College of Occupational and Environmental Medicine's Occupational Medicine Practice Guidelines,” J Occup Env Med 2008;50:282-295.

    • Search Google Scholar
    • Export Citation
  • 3.

    Evans D. Hierarchy of evidence: a framework for ranking evidence evaluating healthcare interventions. J Clin Nurs. 2003;12(1):77-84.

  • 4.

    Guyatt GH, Haynes RB, Jaeschke RZ, et al. Users' Guides to the Medical Literature: XXV. Evidence-based medicine: principles for applying the Users' Guides to patient care. Evidence-Based Medicine Working Group. JAMA. 2000;284(10):1290-1296.

    • Search Google Scholar
    • Export Citation
  • 5.

    Kernan WN, Viscoli CM, Makuch RW, Brass LM, Horwitz RI. Stratified randomization for clinical trials. J Clin Epidemiol. 1999;52(1):19-26.

    • Search Google Scholar
    • Export Citation
  • 6.

    Peduzzi P, Henderson W, Hartigan P, Lavori P. Analysis of randomized controlled trials. Epidemiol Rev. 2002;24(1):26-38.

  • 7.

    Lurie JD, Tosteson TD, Tosteson AN, et al. Surgical versus nonoperative treatment for lumbar disc herniation: eight-year results for the spine patient outcomes research trial. Spine (Phila Pa 1976). 2014;39(1):3-16.

    • Search Google Scholar
    • Export Citation
  • 8.

    Sibbald, B, Roberts C. Understanding controlled trials. Crossover trials. BMJ. 1998; 316(7146): 1719.

All Time Past Year Past 30 Days
Abstract Views 610 610 573
Full Text Views 23 23 0
PDF Downloads 0 0 0