5th Edition PMBOK® Guide—Chapter 2: Project Life Cycle (General Characteristics of Phases)


The topic of the project life cycle is a major one in the 5th Edition PMBOK® Guide, and so I will split it into three posts as follows.

  1. Project Life Cycle (General Characteristics of Phases)
  2. Project Life Cycle (Phase Relationships)
  3. Project Life Cycle Types (Predictive, Iterative/Incremental, Adaptive/Agile)

1. Project Life Cycle: Phases

The definition given by the PMBOK® Guide of a project life cycle is a series of phases that represent the evolution of a product, from concept through delivery, maturity, and to retirement. The reason why a large project may be broken up into phases is because it provides more control over the project and greater clarity with respect to the project deliverables.

A phase has the following characteristics:

  • It is generally sequential, that is, one phase must usually end before the next one starts.
  • It is like a mini-project, in that each phase has all five process groups from initiation through closure.

In fact, if you look at the name of the process 4.6, the last process in the Integration Knowledge Area, it is Close Project or Phase.

Some questions on the PMP or CAPM test may ask about the product life cycle, as opposed to the project life cycle. I must say that the 5th edition of the PMBOK® Guide makes this distinction somewhat clearer in its definitions than in the previous editions;

Term Definition
Product Life Cycle The series of phases that represent the evolution of a product, from concept through delivery, maturity, and to retirement.
Project Life Cycle The series of phases that a project passes through from its initiation to its closure.

The thing that these definitions have in common is that the life cycle is split up into a series of phases in each case. The thing that is different is that in the case of a product, you are dealing with the evolution of a product, and it is possible that some of these phases of a product’s life cycle, especially the design phase, may turn into a project in and of itself. But in the end, the different phases of a product’s life call for different approaches to the work, some involving projects, some involving operational work.

However, whatever the objectives of the project are, a project life cycle is just a way of better managing a project.

2. Project Life Cycle—Trends over Time

Here’s a graph that represents the cost of changes and the stakeholder influence, risk, and uncertainty during the course of a typical project life cycle.

(image taken from leadinganswers.typepad.com)

The PMBOK® Guide mentions the following principles related to this graph.

Start of Project End of Project
1. Risk and Uncertainty Greatest Least
2. Stakeholder Influence Greatest Least
3. Cost of Changes Least Greatest

The risks and uncertainty are greatest at the beginning of the project, and gradually decrease through the course of the project. This is because risks are events which may occur at different points along the way. The farther you get along the way, therefore, the more of those “risk points” have been passed, and therefore the risk decreases as you go along.

The stakeholder influence is the greatest at the beginning of the project as well, which is why the initiating and planning phase are so important. It is not the case that stakeholders will give their opinions as to what should we done less and less as the project goes along; it’s just that their ability to translate their opinions into actually changing the project will decrease as the project goes on. And why is that?

Because of the third relationship, the cost of changes as the project goes on. The cost of changes is the greatest towards the end of a project, and that is one reason why the stakeholder’s ability to influence the project decreases.

These relationships are important and they drive a lot of the reason for PMI’s focus on stakeholder management (part of the Stakeholder Management knowledge area) and on managing change requests (part of the Integration Management knowledge area).

Note, however, that the cost of the project in general does NOT follow the cost curve above. The costs of the project are low in the beginning in the initiating and planning process groups, rise to their height during the execution and monitoring & controlling process groups, and are low again towards the closing process group (after the bulk of the work has been completed). It’s only the cost of changing the project that keeps going up and up until the very end of the project.

The second and third posts in this series show how the different phases can be set up, and the different ways they can be planned, respectively.

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