Comparison of Treatments and Data-Dependent Allocation for Circular Data from a Cataract Surgery

• Activity Number: 232
• Type: Contributed
• Date/Time: Monday, August 1, 2011 : 2:00 PM to 3:50 PM
• Sponsor: Biometrics Section
• Author(s): Somak Dutta*+ and Atanu Biswas and Arnab Kumar Laha
• Companies: The University of Chicago and Indian Statistical Institute and Indian Institute of Management
• Keywords: Circular data ; Ethical allocation ; Optimal allocation ; Response-adaptive design ; von Mises distribution

Abstract

Circular data is a natural outcome in many biomedical studies, e.g. some measurements in ophthalmologic studies, degrees of rotation of hand or waist, etc. With reference to a real data set on astigmatism induced in two types of cataract surgeries we carry out some two-sample testing problems including the Behren-Fisher type of test in the circular set up. Response-adaptive designs are used in phase III clinical trials to allocate a larger proportion of patients to the better treatment. There is no available work on response-adaptive designs for circular data. Here we provide some response-adaptive designs where the responses are of circular nature, first an ad-hoc allocation design, and then an optimal design. Detailed simulation study and the analysis of the data set including redesigning the cataract surgery data are carried out.