The Organization Breakdown Structure (OBS) is the organization chart that will set the roles and responsibilities for the project team in delivering the project’s scope of work. Those could include the project schedule activities as well as the many different project management processes needed to manage the project delivery.
When a WBS package is assigned an OBS responsibility, this will become what is known in project management as a Control Account (CA). The assigned OBS responsibility will be also called a Control Account Manager (CAM). This will enable the control account manager along with the project team members to further decompose the project scope of work into schedule activities, identify the level of effort needed to deliver those activities and the associated cost and project deliverables needed to deliver the contract account scope of work.