In project management, resource smoothing is defined by A Guide to the Project Management Body of Knowledge (PMBOK Guide) as a "resource optimization technique in which free and total float are used without affecting the critical path" of a project.[1] Resource smoothing as a resource optimization technique has only been introduced in the Sixth Edition of the PMBOK Guide (since 2017) and did not exist in its previous revisions. It is posed as an alternative and a distinct resource optimization technique beside resource leveling.