How can I use rowSums() after multiple imputation with MICE package in R

Question

I have a short question:

I imputed item data using multiple imputation with the MICE package.
After imputation, I would like to sum items to a total score.
However, my data is now in a mids object, and I can't figure out how to do this simple task.
Does anyone have experience with this "problem"?

Answer 1

I figured it out:

1. Create an object that contains all imputed datasets and the original dataset
2. Apply the rowSums()
3. Reconstruct the .mids object

Example code:

# load .mids object
library("miceadds")
Dmi<-load.Rdata2("imp.Rdata",paste(getwd(),"imp",sep=""))

# create object that contains all imputed datasets and the original dataset
D<-complete(Dmi,"long",include=T)

# use rowSums
D$T<-rowSums(D[2:11])

# reconstruct .mids object
Dmi<-as.mids2(D)