A project management plan – from the summarized view of the project owner - comprises the following planning steps, with corresponding planning results.
Here is a graphical overview:
Creating a project plan means following these five steps and producing the corresponding results. It looks like a linear, step-by-step process we have to run through once and are done.
In real life, we observe that project planning rather is a process that goes through many loops. We usually follow the planning steps up to a certain point where we suddenly find that we need to go back to an earlier step in order to adjust something before we can continue.
We create PBS, WBS, then enter a first risk analysis and find some high probability and high impact risk event. We find a preventive action which as such is not yet integrated into our WBS. So, we go back to the first step and check to which work package that preventive action can be added. Some larger preventive actions even form new work packages we need to incorporate into our WBS. Then we continue with effort estimation and the next round of risk analysis, and so on.
After completing estimating effort and risks we set up the milestone plan and continue with drawing the network diagram. After translating the first draft of network diagram into a Gantt chart we find out that we do not meet a certain milestone but we know that we have to keep that milestone. So we go back into our network diagram and adjust it until the corresponding Gantt chart shows that we can meet the required milestone.
Project management planning is a recursive task by going through several loops in order to optimize the project plans. The following picture shows a few examples of such back loops.