Dear R listserve,

I am writing with the hope or receiving assistance using the MICE package.My troubles relate to post-processing imputations. I am attempting to impute variables for which I want to specify two conditions using post-processing imputation: 1) if the value of a variable representing the pesticide application (PESTICIDE) is coded 0 to represent that the participant did not conduct task then I want my duration of work in the task (DURR) and start year for the task variables (START_DATE) to be coded as NA; 2) If the value of the variable representing pesticide application task is coded 1 (did conduct task), then I want my duration of work in the task and start year for the task to be imputed  using certain boundaries (restricting the values of the imputed date and duration variables).

The two statements seem to work independently (post-processing statements are recognized); however, I can't figure out how to combine them in one post statement . Thus, I can't get my imputations to take the two conditions into account; I can either restrict the variables to be set to missing if PESTICIDE is 0, or I can get my imputations to be restricted to my specified boundaries, but I can't get R to take both conditions into account simultaneously.

The following is the code that I am using. I am highlighting the two post processing statements that I am having trouble with.:

ini<-mice(agrican.subb,  print=FALSE, max=0)
pred<-ini$pred

pred["START_DATE",]<-1
pred["END_DATE",]<-0
pred[,"END_DATE"]<-0
pred[,"START_DATE"]<-0
pred[,"YEAR_BIRTH"]<-0
pred[,"year_ten"]<-0

pred[,"DIFF"]<-0
pred[,"ID"]<-0
pred[,"CORN"]<-0

method<-c(""," ", "", "", "", "norm", "", "pmm", "", "", "", "", "", "", "norm")

post<-ini$post

post["START_DATE"]<-"imp[[j]][,i]<-squeeze(imp[[j]][,i],c(agrican.subb$YEAR_TEN, agrican.subb$ENROLLMENT_YEAR))"
post["START_DATE"]<-"imp[[j]][p$data$PESTICIDE[!r[,j]]<1,i]<-NA"

post["DIFF"]<-"imp[[j]][,i]<-squeeze(imp[[j]][,i],c(0, 0))"
#post["DIFF"]<-"imp[[j]][p$data$PESTICIDE[!r[,j]]<1,i]<-NA"

imp<-mice(subb,post=post, pred=pred, seed=2332, method=method, maxit=3)

I will appreciate any advise that you can offer.

Thanks in advance!
Leah

Postdoctoral fellow
Section of Environment and Radiation
International Agency for Research on Cancer
150, cours Albert Thomas
69372 Lyon Cedex 08
France
schinasil@fellows.iarc.fr
Tel: [+33] (0)472 73 84 85


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