This includes a couple additions to the original, fantastic Lean Model Canvas. After many sessions, we found that two categories — Constraints and External Forces — kept factoring into how decisions were made.
Constraints include any limitations that affect the other areas on the canvas: budget, team size, timeline, technology, etc. These are commonly, though not necessarily, internal factors.
External forces are, well, external to the organization. Michael Porter's Five Forces is a good place to start for competitive matters. Also consider cultural or industry trends and regulation,
