One of my client / employer hast given this criteria - ROI by Campaign, Site, and Category. Please describe or provide any reference.
ROI: Return in Investment look here : http://adwords.google.com/support/aw/bin/static.py?hl=en&topic=27462&guide=27459&page=guide.cs i don't know what is your site do, but the general detail of ROI is there..