Found this article while putting together a loyalty metrics scorecard (that will be covered in a later post).   In short the KPI’s are

Landing-page exit ratio = site exits from landing page/landing-page visits

Home-page-effectiveness index = home-page-entry visits/visits that proceed down the path toward a defined goal

Thank-you-page abandonment rate = site exits from thank-you page/thank-you-page visits

Actually,  Jason Burby does not give 4 KPI’s but 3.  Read the article - most of these data is not too hard to pull.