A sensitivity analysis for subverting randomization in controlled trials.
In some randomized controlled trials, subjects with a better prognosis may be diverted into the treatment group. This subverting of randomization results in an unobserved non-compliance with the originally intended treatment assignment. Consequently, the estimate of treatment effect from these trials may be biased. This paper clarifies the determinants of the magnitude of the bias and gives a sensitivity analysis that associates the amount that randomization is subverted and the resulting bias in treatment effect estimation. The methods are illustrated with a randomized controlled trial that evaluates the efficacy of a culturally sensitive AIDS education video.
Division of Biostatistics, Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, 622 Blockley Hall, 423 Guardian Drive, Philadelphia, PA 19104-6021, USA. smarcus@cceb.upenn.edu
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D000163:Acquired Immunodeficiency Syndrome / Q000517:prevention & control; D000293:Adolescent; D001741:Black or African American; D003466:Cultural Characteristics; D006266:Health Education / Q000379:methods; D006801:Humans; D015233:Models, Statistical; D011379:Prognosis; D016032:Randomized Controlled Trials as Topic; D015983:Selection Bias; D012680:Sensitivity and Specificity