This is increasingly an absolute necessity for Customer Success execs who want to keep their job and those of their team members. There are two basic approaches: intuitively, and empirically. Start with the intuitive as it’s easier, but don’t stop there. Proceed to gather the data for an empirically based case — making sure that your CFO agrees with your figures.
Ed Powers, of Service Excellence Partners, has written an excellent explanation in Customer Success Central. Here’s the link: