When evaluating processes associated with the process groups, it is important to note that the output of one group becomes the input for another group, and there is overlap between the processes in order to achieve the end result.
Many of the deliverables of one phase are needed and utilized in the following phases, and inputs and outputs for each of the processes depend on the phase in which they are ultimately carried out. The processes are ongoing activities throughout that phase of the project and are not one-time occurrences. The overlap allows the transition from the closing out of one phase and the start of another phase, while linking the results and deliverables that they produce.
Figures 2.1, 2.2, and 2.3 show the links, overlaps, and interactions of the process groups and phases. Figure 2.1 shows how the Initiating process information flow feeds into the Planning processes. This information then flows into the Executing, Controlling, and Closing processes. It also shows how the flow of information goes both ways between the processes (after the Initiating processes, through the intermediate processes, until the Closing processes).
Figure 2.1. Links among process groups in a phase.
Figure 2.2. Overlap of process groups in a phase.
Figure 2.3. Interaction between phases.
Figure 2.2 shows the relationship between time and the level of activity associated with each of the processes and how they overlap. The level of activity includes actions provided by team members or stakeholders while performing work associated with the project. When looking at the diagram, it becomes apparent that the Executing processes have the highest level of activity and the Planning processes have the second-highest level of activity.
Although the level of activity for the Controlling processes is not the highest, it has the longest duration because the project manager is required to maintain control throughout the entire project. The Initiating processes begin the project and merge into the Planning processes. The Initiating processes are completed as the Planning processes' activity levels peak. The Planning processes then merge into the Executing processes, which have the highest level of activity.
The Planning processes continue at a diminished activity level until they merge with the Executing processes into the Closing processes as the project comes to completion. The Closing processes complete the project; as you see, the Controlling and Executing processes' activity levels also descend into the completion.
Figure 2.3 shows how the various phases interact with each other and the flow of information as a subset of the each phase. As a project manager, you must acknowledge that the phases are interdependent but also separate entities. The inputs and outputs for each of the processes are directly affected by the phase in which they occur, and there is frequent overlapping of the actual processes.
It is easiest to think of the phases in sequential order, with one phase having an impact on the subsequent phases. This figure also shows how the closing of one phase provides the input to begin the next phase. Because the project is an ongoing process that tends to draw information and details from previous phases in order to complete the current one, the project plan uses rolling wave planning to show these details.
It is highly recommended that you involve stakeholders throughout the phases in order to gain buy-in and increase your probability of success. Buy-in defines the agreements between team members and stakeholders that encourage participation and elicit feedback from the participants in order to come to consensus. This tool is one of the fundamentals of effective project management and is used frequently to develop cohesiveness and camaraderie among team members and stakeholders.
The PMBOK focuses on describing each process in terms of the inputs, outputs, tools, and techniques. It defines inputs as "documents or documentable items that will be acted upon." Outputs are defined as "documents or documentable items that are a result of the process." Furthermore, tools and techniques are "mechanisms applied to the inputs to create the outputs." Thus, you can see how all these links are interrelated.