The next section of the PMBOK expands on the processes, discusses some of the exceptions, and explains the fact that not all the processes are utilized on every project. Smaller projects tend to be more simplistic and may not require an extensive amount of planning or control management.
Planning processes can change or alternate due to variables such as the use of contractors and the availability of unique resources, such as physicians, computer specialists, or scientists. Because of the complexity of larger projects, more details and elaboration of tasks are required.
Consequently, the Work Breakdown Structures (WBSs) for complex projects can be huge and very elaborate. Many times the emphasis of a project plan is based on the budget for the project, and whether it is a high-profile project that has a major impact on the organization. Because many projects have time constraints, this may predefine some of the process outputs and reduce the impact of the Planning phase.
The 39 project management processes, nine project management knowledge areas, and five project management process groups are summarized at the end of Chapter 3 of the PMBOK in Figure 3-9, "Mapping of Project Management Processes to the Process Groups and Knowledge Areas." We will continue to elaborate on these areas in the following chapters.