Consider using the haven package for importing SAS, Stata, and SPSS
files; haven stores labels as the label attribute of each variable as
does Hmisc; it converts date and time variables automatically and allows
one to specify a format catalog along with the primary dataset
See if the readstata13 package has advantages over the foreign
package for Stata file import
Consider creating xl.get using the readxl package to read .xls and
.xlsx Excel files
In impute.transcan, sense if a variable in data is not a factor
whereas it was treated as a factor during aregImpute; it should be
converted to factor before the line v[sub] <- … levels(as.integer…))
is run