Comparison Between Bayesian and Frequentist Methods Using Winbugs and SAS for Two Group Proportions from a Comparative Study

• Activity Number: 168
• Type: Contributed
• Date/Time: Monday, August 1, 2011 : 10:30 AM to 12:20 PM
• Sponsor: Section on Bayesian Statistical Science
• Author(s): Aijun Gao*+ and Kyoungah See and Jing Zhang
• Companies: i3 Statprobe and Eli Lilly and Company and Miami University
• Keywords: Bayesian method ; Frequentist method ; Incidence rates ; WinBUGS ; GENMOD ; MCMC

Abstract

A comparative study included about 200 patients appropriate for a treatment therapy. The study assessed a categorical response about the treatment therapy from subjects using it in the community setting to self-administer study drug at baseline and two follow-up visits. There were about 100 patients in the current user group and patients in the non-current user group. Patient response incidence rates and the 95% confidence intervals were estimated using Frequentist methods (PROC FREQ and PROC GENMOD). As a comparison, the incidence rates were analyzed using Bayesian methods (WinBUGS, PROC GENMOD, and PROC MCMC). Different priors were tested to check the sensitivity. Similar results were obtained from Frequentist and Bayesian methods. The Bayesian approach provides immediate interpretation for estimated quantities and predictions and allows possible historical information to be included in studies. It also provides the posterior probability of any event, which makes the comparison of the incidence rates between current user group and non-current user group easier.