A WBS, as defined in the PMBOK® Guide—Third Edition is “a deliverable-oriented hierarchical decomposition of the work to be executed by the project team to accomplish the project objectives and create the required deliverables. Learn about Work Breakdown Structure and How to Make WBS Chart. A work-breakdown structure (WBS) in project management and systems engineering, is a deliverable-oriented breakdown of a project into smaller components. Work breakdown structure (WBS) is a method of organizing and completing work in a project. Dividing complex projects to simpler and manageable tasks is the process identified as Work Breakdown Structure (WBS). A WBS is the cornerstone of effective project planning, execution, controlling, monitoring, and reporting.