Nestled in the hefty breakdown at subscription value by Joe Amditis of The Membership Puzzle Project is a handy tool for calculating how much a news organization could earn from their subscribers.
This spreadsheet is built around the concept of lifetime value (LTV) as commonly applied in software and tech. The assumptions work equally well in the business of news. Subscribers tend to stick around for a period of time and then fall off or cancel, which creates a variety of retention rates and cohorts of subscribers whose behavior can provide insight into expected revenue.
News organizations can use their funnels (Table Stake #4) to define the assumptions outlined in this resource and inform their longer-term understanding of their subscription revenue.