It's pretty simple, really. During the first 90 days, if you implement our Revenue Ramp process, and don't see a 100% ROI (that revenues from the program exceed program costs), then we'll refund the program costs - and you can keep the program materials we gave you.
All you need to do is make sure you're implementing, tracking what you're doing, and tracking sales.
Being completely transparent, there is one detail. If your sales cycle is very long (such that you couldn't really close sales in 90 days), then we measure ROI based on pipeline added rather than deals closed.