American Statistical Association
New York City
Metropolitan Area Chapter

New York State Psychiatric Institute
at Columbia University Medical Center
Biostatistics Seminar



Sue M. Marcus, Ph.D.
Division of Biostatistics & Data Coordination
New York State Psychiatric Institute


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 control trial that evaluates the efficacy of a culturally sensitive AIDS education video.

Biographical Note

Sue M. Marcus is in the Division of Biostatistics and Data Coordination at Columbia/New York State Psychiatric Institute. She received an M.S. in Biostatistics from Harvard School of Public Health and a Ph.D. in Statistics from the Wharton School of the University of Pennsylvania where she did her dissertation under the supervision of Paul Rosenbaum. Dr. Marcus has written and consulted extensively on observational study methods for bias in longitudinal mental health studies. Dr. Marcus is a Research Scientist at the Center for Health Statistics at the University of Illinois at Chicago, a leading center for the development of statistical methods for causal inference in longitudinal studies. She has been a Scientific Advisor to the NIMH multisite TADS trial and statistical consultant for the NIMH multisite Multimodal Treatment for Children with ADHD (MTA) Follow-up Study.

Date: Tuesday, January 26, 2010
Time: 3:00 - 4:00 P.M.
Location: New York State Psychiatric Institute
1051 Riverside Drive
6th Floor Multipurpose Room (6602)
New York, New York


Coffee: 2:45 to 3:00 P.M.
Reception: 4:00 to 4:30 P.M.

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