[amelia] convergence and missing ouput data

Hello, I am new to using Amelia. I have two questions. First, when I run the overdispersed start values diagnostic, it converges to two different modes. Adding priors didn't resolve the problem, so I deleted some variables that were highly correlated and it converged to a single mode. I was hesitant to remove the variables since I want to include as many variables in the imputation model as possible. Is there another way of managing this kind of situation? Unfortunately, I have a high rate of missingness for many variables and a small sample size of 208 countries. Originally, I had 31 variables, but after deleting 6 highly correlated variables, I now have 25 variables, 3 of which are completely observed. I realize that this means I have more parameters than observations, but I don't know what else to do when I can't add any more countries to the sample. With a ridge prior of 1, the imputations seemed to run well, however. Second, with my smaller data set that appears to run well, as soon as I begin running the overdispersed starting values diagnostic, the first imputed data set (outdata1.csv) disappears from the folder leaving only data sets 2-10. Is this an error or should it be deleted for purposes of a burn-in? If this is not an error, should I run 11 imputations to get 10, not using the first data set? Alternatively, should I make a copy of the data sets before running the diagnostics and use the first imputed data set? This has not happened in previous imputation models that I have run, so I have re-run the same model three times and the first dataset appears after running the imputations, but is disappears once I begin running diagnostics. The overdipersed start values diagnostic graph shows that the values do not converge until around 1,000 imputations. I increased the ridge prior to 2 and the same thing happened. I appreciate your response. Erin Saunders Portland State University - Amelia mailing list served by Harvard-MIT Data Center [Un]Subscribe/View Archive: http://lists.gking.harvard.edu/?info=amelia