American Statistical Association
New York City
Metropolitan Area Chapter

Memorial Sloan-Kettering Cancer Center
Biostatistics Seminar

Heejung Bang, Ph.D.
Assistant Professor
Division of Biostatistics
Weill Cornell Medical College


Success of blinding is a fundamental issue in many clinical trials. Knowledge about treatment allocation and its related expectation and behavior could influence study outcomes in trials. Blinding (or masking) aims to eliminate this. The importance of blinding has been repeatedly emphasized by regulatory and advisory agencies for clinical trials such as FDA and CONSORT group. Although thousands of ostensibly double-blind trials are conducted annually and investigators acknowledge the importance of blinding, attempts to measure the effectiveness of blinding are rarely discussed. James et al. (1990) and Bang et al. (2004) proposed blinding indexes (BIs) to evaluate the success of blinding. A module for blinding indexes was released by Stata in March 2008 and is currently being constructed as a web-based repository of blinding data from clinical trials. With this computational tool and resources available, we hope to see more quantitative data and evidence on blinding in the literature. We urge all trials claiming “blind” to report the BI at the end of the trial and make some efforts to understand qualitative as well as quantitative aspects of (un)blinding and share their stories in research communities, which will shed some light on the internal validity and the quality of trials, providing the communities with new elements to interpret their findings and to plan good clinical trials in the future.

Date: Wednesday, May 28, 2008
Time: 4:00 P.M. - 5:00 P.M.
Location: Memorial Sloan-Kettering Cancer Center
Department of Epidemiology and Biostatistics
307 East 63rd Street
(between First and Second Avenues)
3rd Floor Conference Room
New York, New York
Note: To gain access to the building, please follow the directions by the telephone in the foyer.


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