Hi Donald, Amelia does not have the ability to do logical checks of the sort you describe. One approach you could try is treating the rank of each item as an ordinal variable. Of course, this will not preserve the logical consistency within a unit. Depending on your analysis model this might or might not be hugely important. I hope that helps. Cheers, matt. On Tue, Jun 22, 2010 at 7:19 PM, Donald Braman <dbraman(a)law.gwu.edu> wrote: - 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

One more thought upon additional reflection. Another way to express the data such that it contains the same information is to create k* (k-1) binary variables, each of which rank the data as "is object A preferred to object B". These would all be dichotomous. This is the old-school numerical way of running an ordered probit model--constructing all these variables and then allowing each to have a unique intercept term. Some of these dichotomous variables would be missing if either A or B were missing in your data, that is, you don't know if A or B is higher ranked. With the data in this format, everything would be congenial to the multivariate normal assumptions of Amelia and the standard multiple imputation model. You could run the Amelia algorithm on this data. Sometimes you would end up with imputations of all these k*(k-1) new variables that were not transitive, which would be a violation of what we know to be true. Matt Blackwell has written a rejection sampler for Amelia that is described in the Amelia manual. You could rejection sample all imputations that violate transitivity. This would be a model that would be very reasonable given k=5 ranked data and reasonably immediately implementable with the current library. James Honaker On Wed, Jun 23, 2010 03:12 PM "JAMES HONAKER" <tercer(a)psu.edu> wrote: - 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