Dear Amelia Listers I have a data set which gives me the counts of a number of religious groups, in 3 cities for 60 years. I use these counts to generate an index for religious diversity in each available year. I had missing data, which I imputed using AmeliaII in R. I included both the counts and the index to generate the imputed values, and then used the "new" counts to generate the index again (overwriting the imputed index). I also generated a number of other variables using the index (squared, interactions etc). I gather the originally imputed data and my new variables using: #####   begin code      #####        a.out.final <- a.out        for(i in 1:10){                <create new variables>                a.out.final$imputatations[[i]] <- cbind(a.out$imputations[[i]], <new variables>)        } #####   end code        ##### where a.out is the original Amelia output. This works fine, as far as I can see. however, when I now ask for a summary(a.out.final), I get an error message. The first past of the message is the same as for summary(a.out), but then I get: Fraction Missing for individual variables: ----------------------------------------- Error in `row.names<-.data.frame`(`*tmp*`, value = c("cityid", "year",  :  invalid 'row.names' length ("cityid" and "year" are obviously my panel/time indicators ) Does this mean that I have made a mistake, or am trying to do something that cannot be done? Or is it simply due to the fact that Zelig can no longer recognise what was originally missing and what not? I am new to R and Zelig, and such (unintelligible) error messages scare me! Thanks again for your time, Matthijs de Zwaan - 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