MS Excel / VBA help thread

Sorry for the slightly lazy question, but thought it was worth asking before I spend ages working it out for myself only to find out it's too clunky and not worth the hassle.

• xls is used as a questionnaire (very small volume ~10)
  
• 2 sheets.
  
• people need to fill sheet 1 or sheet 2, or both.
  
• ~50% of the content of the sheets is the same.
  
  

Is there are relatively simple IF or similar function to autofill the duplicate data in Sheet 2 from Sheet 2 to reduce people being lazy and not completing both? Even better if there is a way to only do this based on the input into one of the boxes which is a data validation(?) A/B/Both option box.

Or will it be a PITA and just be easier for people to fill/not fill and me work it out after?

Should have thought about it longer!