Probability Seminar
Department of Mathematical Sciences |
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Hongbin Fang
University of Maryland Division of Biostatistics
Title: Bridge logistic regression based on ROC criterion.
It is well known that the bridge regression gives asymptotically
unbiased estimates of the nonzero regression parameters while shrinking
the estimates of zero (or small) regression parameters to zero, implying
potentially better predictive performance. However, to our knowledge,
there is a general lack of corresponding computational methods for
modeling even for bridge linear regression. In this article, we first
propose a new criterion defined by the receiver operating characteristic
(ROC) curve to choose the appropriate penalty parameter instead of the
conventional generalized cross-validation criterion. The model selected
by the ROC criterion is shown to have better diagnostic accuracy while
achieving variable selection at the same time. We then develop a fast
EM-like algorithm for non-linear optimization with positivity
constraints for model fitting. This algorithm is further applied to
bridge regression where the regression coefficients are constrained with
Lp norm with p < 1 for binary responses. Simulations and examples of
prognostic factors and gene selection are presented to illustrate the
proposed method.
©2006, Department of Mathematical Sciences
Last Modified:
May 19, 2007