RE: order of covariate inclusion -> avoiding stepwise approaches

From: gary.maier@sepracor.com Subject: RE: [NMusers] order of covariate inclusion -> avoiding stepwise approaches Date: Friday, September 26, 2003 7:54 AM Hello Marc I think that some of your criticisms of the stepwise approach are right, however as an industrial scientist I believe that we need some sort of acceptable and "easy to implement strategy" in selecting model covariates. If we rely exclusively upon what the modeler believes to be "the relevant set of variables" to examine we introduce too much "art" into the process. The issue then becomes when we send our pop pk reports to FDA there will not be any guideposts for them to follow and the sponsor could end up in endless discussions with regulatory agencies. I think that if stepwise regression is not the answer it is up to the more statistically oriented users to propose an alternative that relies upon some type of statistical guidelines not just art/judgment alone Gary Maier Sepracor gmaier@sepracor.com