To provide timephased cost data, you can link your OBS (which provides your organizational breakdown structure of human resources) to your WBS (which describes the tasks to be performed in the project). Linking the WBS to the OBS assigns the responsibility of the tasks to departments within your organization.
To link the WBS and OBS, assign each WBS control account (task) to an OBS element, which represents the department or organization responsible for completing the task. The resultant grid is called the Responsibility Assignment Matrix (or RAM), also known as a Cost Account Matrix.
The RAM sometimes becomes quite large, but it does provide a useful summary of the work contained in the WBS, and places responsibility for performance of all tasks. A RAM is most helpful when used early in a program, but can also be used during the proposal stage, and can be updated after the program is awarded.
For more information, see Responsibilities Assignment Matrix report.
The example below illustrates a RAM which links the responsible organization tree and its interaction with a WBS:
The example below illustrates a RAM which links the performing organization tree and its interaction with a WBS:
