Rolling wave planning is a form of progressive elaboration planning where the work to be accomplished in the near term is planned in detail and future work is planned at a higher level of the WBS. Therefore, work can exist at various levels of detail depending on where it is in the project life cycle. For example, during early strategic planning, when information is less defi ned, work packages may be decomposed to the milestone level. As more is known about the upcoming events in the near term it can be decomposed into activities.