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November 16, 1984

Scientific Challenges in the Application of Randomized Trials

Author Affiliations

From the Departments of Epidemiology and Health (Drs Kramer and Shapiro) and Pediatrics (Dr Kramer), McGill University Faculty of Medicine, Montreal.

JAMA. 1984;252(19):2739-2745. doi:10.1001/jama.1984.03350190041017

In recent years, scientific challenges in the application of randomized trials have become more apparent, especially with the extension of such trials to the assessment of nondrug treatments, such as health education, psychotherapy, and health care provision. Six issues (individual v group randomization, blinding and unblinding, the effect of trial participation on outcome, selective subject participation, treatment compliance, and standardized v individualized treatment) are discussed in terms of their impact on internal validity, generalizability (external validity), and clinical relevance. Specific design strategies may be necessary to enhance these methodological and clinical desiderata. Attention to these challenges should lead to improvements in future randomized trials.

(JAMA 1984;252:2739-2745)