Projects are divided into manageable segments by establishment of a WBS (Work Breakdown Structure). The structure is agreed at the outset of the project by Project Management, Engineering Management, Construction, Project Controls, and the client.

The structure varies with the size and complexity of the project, as well as client reporting requirements. The WBS serves the control needs of the project by providing a structure for performing work and defining how work is summarized and reported. It may be as simple as a Code of Accounts for a small project or as complicated as a “tree” diagram indicating the summarization path for schedules.