I am hoping that someone on the Zelig mailing list might be able to help me with the following question. I had previously posted it on the R-help list but didn't get any replies. I need to estimate a model that predicts the proportional split of travel among the vehicles of a household based on vehicle characteristics such as age, fuel economy, and travel cost per mile. The model estimation dataset has a record for each household vehicle with information about the vehicle, the household, and the proportion of the total household vehicle travel using that vehicle. I have not been able to figure out how use multinomial logit estimation functions in R to predict proportions rather than categorical probabilities. I have found from searching the web that there is a Stata function, FMLOGIT, that will do what I want. Does anyone know how this can be done in R? All of my model estimation scripts for the large model I'm building are in R and I would like to keep it that way to create a nice replicable set of scripts and data to document the model. Thanks much. Here's some additional information. I am currently using linear regression to estimate the model. Then in application I scale the proportions coming from the model for the vehicles in each household by dividing by their sum. Perhaps that is good enough. Brian Gregor Senior Transportation Analyst Oregon Department of Transportation Transportation Planning Analysis Unit 555 13th Street NE Salem, OR 97301 503-986-4120