James P. Hobert Department of Statistics University of Florida Location: Carslaw 173 Time: 2pm Friday, June 10, 2011 Improving the Data Augmentation Algorithm Abstract: After a brief review of the data augmentation (DA) algorithm, I will introduce a simple modification that results in a new Markov chain that remains reversible with respect to the target distribution. We call this modification the "sandwich algorithm" because it involves an extra move that is sandwiched between the two conditional draws of the DA algorithm. General results will be presented showing that the sandwich algorithm is at least as good as the underlying DA algorithm in terms of both efficiency and convergence rate. An example will be used to demonstrate that, in practice, massive gains are possible. (This is joint work with K. Khare, D. Marchev and V. Roy.)