What is a work breakdown structure and how is it created?

A work breakdown structure, or WBS, is a hierarchical decomposition of the total scope of work into smaller, manageable components called work packages. It is created by taking the project scope and progressively breaking it down into increasingly detailed levels. The top level is the project itself, the next levels represent major deliverables or phases, and the lowest level contains work packages small enough to be estimated, scheduled, monitored, and assigned. The WBS does not describe activities or tasks but deliverables.