There has been a lot of good stuff written over the years on the topic of calculating customer lifetime value (LTV). Thus, it amazes me how many times I discover faulty thinking when I talk to entrepreneurs regarding their LTV math.

One portfolio company executive confessed to me last week that he knows he is doing it wrong but he just didn't have the time to research the best way to do the LTV calculation. Since I see a few common patterns of mistakes, I thought I'd add to the LTV literature and point out the top three reasons many investors roll their eyes when they see entrepreneurs present inflated, poorly constructed LTVs...