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2 - PROJECT LIFE CYCLE AND ORGANIZATION

• Construct: Software Construction Process,

• Integrate: Software Integration Process, and
• Test: Software Qualification Testing.

For purposes of exposition, this Software Extension will use these six processes (analyze, architect, design,
construct, integrate, and test) to describe the software project life cycle variations found in the software industry.

Figure 2-9 of the PMBOK Guide illustrates cost and staffing levels across the project life cycle. The figure
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depicts a profile that rises during initiation and planning, peaks during execution and monitoring and controlling,
and decreases during project closure. This profile is typical for predictive software project life cycles. Adaptive
software life cycles tend to lower the peak of cost and staffing level during the execution and monitoring-and-
controlling phases and shift the entire profile to earlier stages. This is possible because adaptive life cycles validate
increments of working software on a continuing basis to minimize the impact and cost of subsequent changes. In
addition, adaptive life cycles that maintain a constant staffing level during execution and monitoring and controlling
tend to flatten the profile during those elements of software project life cycles.

2.4.2 Project Phases

2.4.2.1 Phase-to-Phase Relationships

According to the PMBOK Guide, there are two basic types of phase-to-phase relationships: sequential and
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overlapped. The nature of software allows for significant flexibility in overlapping, interleaving, and iterating
software development phases. ISO/IEC/IEEE Standards 15288 and 12207 use the term stages rather than phases
to indicate that these stages are to be used throughout a project whenever they are needed to achieve project
objectives. Highly adaptive software project life cycle models, for example, execute many of the stages during each
iterative cycle, as explained in Section 2.4.2.4 of this Software Extension.

2.4.2.2 Predictive Life Cycles

Section 2.4.2.2 of the PMBOK Guide defines predictive life cycles as those for which the project scope, and the
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time and cost required to deliver that scope, are determined as early as practically possible in the project life cycle.
A predictive life cycle model for software projects, as illustrated in Figure 2-2, is characterized by a sequence of
overlapping development phases with feedback to and repetition of previous phases as needed.

Each of the overlapping circles in Figure 2-2 includes the five Process Groups of the PMBOK Guide:
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Initiating, Planning, Executing, Monitoring and Controlling, and Closing processes (see also Figure 3-1 of
the PMBOK Guide). The processes in each Process Group are conducted for the six phases in a sequential
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or overlapping manner. Some processes in earlier phases may be repeated, based on feedback from later
phases. Phases may be overlapped in time, as indicated in Figure 2-2, or they may be executed sequentially.

28 ©2013 Project Management Institute. Software Extension to the PMBOK Guide Fifth Edition
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