This process provides detailed information for estimating and scheduling as well as a baseline for project control. Scheduling, in comparison, is the determination of the timing and sequence of operations in the project and their assembly to give the overall completion time. The schedule is obviously a reflection of the plan, but the plan must come first. The process of scheduling may uncover flaws in the plan, leading to revisions, but the plan is still first in the hierarchy. Planning involves making decisions about what task will be performed, how the task will be performed, who will perform the task, and when and in what sequence the task will be performed.
Planning is performed at various levels at various times during the execution of a project.
In turn, each of these participants provides additional planning at a more detailed level to further anticipate and make the decisions concerning alternatives related to his or her specific area of responsibility. A significant part of the planning process involves learning from history. Planning generally involves approximately 80 per cent memory of historic procedures and 20 percent synthesis or creative thought. Documentation of the plan provides a benefit to the project participants in providing a formalized, systematic learning process. A construction project schedule may mean different things to the owners, designers, contractors, subcontractors, and suppliers involved in the construction process.