Newbie here.

I am trying to merge two files - one is a headteacher survey from 200 schools. The second is a parent survey carried out with 6 parents from 60 schools (so 360 observations in total) randomly selected from the 200. Both have the variable SchoolName as the identifier.

I have tried the following:

Using the parent file as the master one and the command "merge 1:m SchoolName using" the parent file. I've also tried the command merge m:1. It keeps returning the message "that variable SchoolName does not uniquely identify observations".

I have searched for duplicates and found none.

I've checked SchoolName is stored as a number in both files.

Thank you for your help.