I have a survey that people fill in twice. The first time they get a set of questions say A, B, C, D
After a week they get a second set: A (no need to change anything there but just look at they previous answer), E, F, G
I then need to compare B with E, C with F and D with G
The way I put it together is that I use a date field that is not visible to the users.
Questions BCD are shown only the first time (condition set against the non-visible date) while EFG are shown only during the second time (again the same trick with the date)
Unfortunately, when people fill in EFG, the answers on BCD are set by the system back to NULL. This way I cannot compare anything