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Planning Lifecycle in the PMBOK Guide

~ By Nader Khorrami Rad

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Which one of the five process groups in the PMBOK Guide has the largest number of processes?

Yes, you have probably answered correctly; that's the planning process group. This group usually has about 50% of the whole processes defined in the standard. This percentage was more or less the same in all editions, as shown in the following diagram:

Percentage of the planning process diagram

So, how does the planning happen?

You can certainly understand it by following the relationship among processes, which itself is derived from inputs and outputs of them (when one of the outputs of one process is also an input to another process, we will realise that they have a direct relationship). This would be too detailed, and you'd better have a big picture first, by understanding the planning lifecycle. This is going to be explained in this article.

1. Simplest Form of Planning

The following diagram shows what we are supposed to do in normal situations according to the PMBOK Guide:

Simple form of planning diagram

It has two important points:

  • You should not start executing unless your initial planning is finished.
  • You should not stop revising plans (progressively elaborate them, in PMBOK terms) until the executing ends.

The first one is straightforward. How do you execute the work? Do you just start doing it, and see what happens? And then decide on your immediate actions? That's not PMBOK compatible. You should take the most out of your resources, and that's not possible without having full control over them. Having control needs you to be proactive and being so is impossible without planning. You should plan everything, and it's not limited to the activities you are aware you should do, but also covers other thing like the uncertainties (risks), and extra tasks you perform to be sure of the final result (quality).

Executing is not starting the work and seeing what happens; it is "doing the plan", based on the PMBOK Guide. In these terms, you cannot execute if you don't have a plan.

Suppose we have a complete and detailed plan in place, and we can start executing. Now what? Is it possible to consider executing as "doing the plan" and use the same plan for the whole time of the project? Of course not. You need to revise your plan regularly and keep it in shape, in order to be able to define executing as "doing the plan".

2. Planning for Multiple Phases

It's common to divide large and complex projects into phases, in order to make project management easier. Each phase produces a major deliverable and is usually necessary to define the next phase. It's possible for the phases to overlap a little, but the normal form is zero-overlap.

Multi-phase planning diagram

This diagram shows a project with three phases. Each phase is planned and executed like a single project, and an overall, high-level plan governs the whole project.

We still have the two previous important points, in addition to the following ones:

  • When we do not plan the whole project in detail in the beginning, we have to prepare a high level plan instead. In other words, we need to have a complete plan covering 100% of the project scope in the beginning, even if we have to keep it high level.
  • And yes, even the high level plans need revisions all the way.

3. Rolling Wave Planning

The other type of planning happens when we do not have such major deliverables needed for defining phases (or just we are not willing to divide the project into phases for some reason), and we cannot plan the whole project in detail in the beginning. Suppose we have a design-build project; can we plan the "build" part in the beginning, when we have not "designed" it yet?

The rolling wave planning is used in such situations. We will prepare the high level plan of the whole project in the beginning and keep detailing the near future as time passes by and our understanding or knowledge of the project increases.

This would be the rolling wave planning model of the PMBOK Guide:

Rolling wave planning diagram

"DP" in this diagram stands for detailed planning. Each number represents a time period of executing.

So we prepare a complete high level plan for the whole project before executing, following by continues revisions which will last until the end of the executing. Underneath the high level planning efforts, the detailed planning and executing of multiple time periods happen.

We have the previous four points plus the following:

  • We are not allowed to start executing the work of a given time period, unless we have planned it in detail beforehand. In other words, saying that “we are using rolling wave planning” is not a license for giving up appropriate planning and work without a previously prepared, examined, and approved detailed plan.

Time periods in rolling wave planning are flexible and depend on the project environment. You don't even have to have the same size time periods.


We can derive all three types of planning methods by the following rules:

  1. We should prepare a complete plan at the beginning of the project and before executing the project work, covering the whole scope of the project. If the whole project is determined enough, we should plan it in detail, and if it's not possible (logically not possible, not impossible based on trying to fast track or based on laziness) we should keep it high level.
  2. We are not allowed to start any package of work, unless it was previously planned in detail.
  3. We should always keep revising the plans.

If you do not follow any of these rules, you would not be working PMBOK Guide compatible (or compatible with any other systematic approach that I'm aware of).

Nader Khorrami Rad is a project management expert with 12 years of experience. A PMP, CSM, and PSM-I certified civil engineer with a Philosophy of Science master's degree. He is the author of 38 books in Persian and 3 ebooks in English. His latest publication is a free ebook titled "Understanding the PMBOK Guide", which you can download from his website PMarchy. Connect with him on Twitter @KhorramiRad.


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