Land management agencies need to understand and monitor the consequences of their fire suppression decisions. We developed a framework for retrospective fire behavior modeling and impact assessment to determine where ignitions would have spread had they not been suppressed and to assess the cumulative effects that would have resulted. This document is a general guidebook for applying this methodology and is for land managers interested in quantifying the impacts of fire suppression. Using this methodology will help land managers track the cumulative effects of suppression, frame future suppression decisions and costbenefit analyses in the context of past experiences, and communicate tradeoffs to the public, non-government organizations, land management agencies, and other interested parties.