Classification rates on out-of-sample predictions can often be improved thr
ough the use of model selection when fitting a model on the training data.
Using correlated predictors or fitting a model of too high a dimensionality
can lead to overfitting, which in turn leads to poor out-of-sample perform
ance. I will discuss methodology using the Bayesian Information Criterion (
BIC) of Schwarz (1978) that can search over large model spaces and find app
ropriate models that reduce the danger of overfitting. The methodology can
be interpreted as either a frequentist method with a Bayesian inspiration o
r as a Bayesian method based on noninformative priors.