Re: Probabilistic model

From: Chuanpu.Hu@sanofi-aventis.com Subject: Re: [NMusers] Probabilistic model Date: Tue, May 17, 2005 10:29 am While treating categorical variables as continuous allows better estimation, often it is improper because the categories are not homogenious. For example, difference between category 1 and 2 is usually not comparable to that between category 2 and 3. Combining caegories will make sense if one does not care whether the category is 1 or 2, and the main objective is to assess the probability of, say, <=2 vs >2. However, if that is not clear a priori, then combining caegories would lose information indeed. I suspect that the problem still lies in over-parameterization, e.g., the number of ETAs, based on the phenominom Leonid describes. Chuanpu ------------------------------------------------------------------- Chuanpu Hu, Ph.D. Biostatistics sanofi-aventis 9 Great Valley Parkway Malvern, PA 19355-1304 Tel: (610) 889-6774 Fax: (610) 889-6932