Peter Müller, Ph.D.
Professor of Biostatistics
The University of Texas M. D. Anderson Cancer Center
Houston, Texas U.S.A.
Pre-Posterior Simulation and Bayesian Optimal Design
Many Bayesian design problems
require the solution of analytically intractable integration and optimization
problems. We will discuss three related approaches. The first is optimal design
by curve fitting of Monte Carlo samples. Second, we will propose an approach to exploring
expected utility surfaces by pre-posterior simulation. By artificially augmenting the usual
statistical model, p (theta, y) for a parameter, theta, and data, y, to a probability model h (d, theta, y) that includes the decision
vector, d, the optimal design problem
is recast as a problem of simulating from this augmented distribution. We will also
discuss a generalization of this augmented probability model that is similar to
the power transformation in simulated annealing. Another practically important but notoriously
difficult class of problems is sequential decision-making. We will discuss some
recent simulation-based methods for approximate solutions to sequential design
problems. We will begin with a general
review of simulation-based methods in Bayesian inference, including designs
based on inference loss, expected utility optimization, and stylized Bayesian
design. Biostatistical applications will include adaptive dose allocation in
phase I/II trials, dose individualization, and optimal sampling for
longitudinal data.
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