[amelia] How can I make a function to run several regression models using imputed data with Amelia?

I have a multiply imputed dataset (imputed using Amelia) and would like to derive a function which runs several regressions (with the same outcome, and different predictor variables) in one go. The reason is that I need to run several regressions (with the same predictors) on different outcome variables. I have defined the function but when I run it, I get an error message: Error in model.frame.default(formula = outcome ~ country, data = as.data.frame(.), : variable lengths differ (found for 'country') I think it is because the imputed datasets are an "amelia" object and not a typical data frame, so it is hard to index the variable "country". But I'm not sure how to do this. A reproducible example is below. I would really appreciate any advice. library(Amelia) library(Zelig) # Use africa dataset data(africa) # Impute data imp.out <- amelia(x = africa, cs = "country", ts = "year", logs = "gdp_pc", m=5) summary(imp.out) # Define function to run regression predicting an outcome from country, gdp_pc, civlib, and population reg_function <- function(outcome, data) { # Run regressions using the zelig function country <- zelig(outcome ~ country, model = "normal", data=data, cite=FALSE) gdp_pc <- zelig(outcome ~ gdp_pc, model = "normal", data=data, cite=FALSE) population <- zelig(outcome ~ population, model = "normal", data=data, cite=FALSE) # Put results into a vector results <- ( c(combine_coef_se(country)[2,1], combine_coef_se(country)[2,2], combine_coef_se(gdp_pc)[2,1], combine_coef_se(gdp_pc)[2,2], combine_coef_se(population)[2,1], combine_coef_se(population)[2,2])) # Return results in a matrix return(matrix(results, nrow=1, ncol=6, dimnames=list(c(""), c("Est_country", "SE_country", "Est_gdp_pc", "SE_gdp_pc", "Est_population", "SE_population")))) } # Run regression for outcome variables "year", "infl", and "trade" # This is where I get the error messages that the variable lengths differ for 'country' year <- reg_function(year, imp.out$imputations) year <- reg_function(infl, imp.out$imputations) year <- reg_function(trade, imp.out$imputations)