Hi Shanruo, If you don't want to include the NAs in the analysis at all, you can remove them from the data and then run the imputation model. You could also leave them in the imputation, but then change their imputations back NA manually. Note that any cell that needs to be imputed must be coded as "NA" (the missing value code for R). An alternative method would be to code all NAs as another category of the variable which is observed. Only DKs would then be missing. Hope that helps, matt. On Fri, Jan 22, 2010 at 6:33 PM, Shanruo Ning Zhang <nizhang(a)calpoly.edu > wrote: > Hello, Amelia authors and users, > My co-author and I wonder whether we could separate different types > of > missing data when using Amelia, namely the Don't Knows and the > Non-applicable's. We wonder whether it is possible that we could > impute > values for the DKs and not impute for NAs. > Thank you very much. we have been really enjoying Amelia! > Best, > Shanruo Ning Zhang > Assistant Professor > Political Science, California Polytechnic State University, San > Luis Obispo > - > Amelia mailing list served by Harvard-MIT Data Center > [Un]Subscribe/View Archive: http://lists.gking.harvard.edu/?info=amelia > More info about Amelia: http://gking.harvard.edu/amelia > >