1.7 WBS Evolution. Throughout any systemís life cycle,
systems engineering leads system development. This function includes
developing system specifications, functional specifications, or a set of
configuration items through requirements analysis, functional analysis and
allocation, synthesis and systems analysis, and controls. The important
factor is satisfying total systems cost, schedule, and performance
requirements at an acceptable level of risk.
As the system is defined and developed, the DoD program manager can better
understand and identify the WBS structure that is appropriate for the program.
Figure 1-1 provides an illustration of the system life cycle.
FIGURE 1-1. The Defense Acquisition Management
Through the Concept Refinement to the Technology Development phase, the
program WBS is usually in an early stage of development. The results
of the Analysis of Material Approaches and the Analysis of Alternatives
(AoA) provide the basis for the initial WBS.
Since the system is mainly a concept at this point, it is not until the
System Development and Demonstration (SDD) phase that the system is broken
into its component parts and a detailed WBS can be developed. In the SDD
phase, configuration items that describe the Program WBS are first
identified and contracts can be awarded to develop these items. By the
end of SDD, the WBS is fully defined to its lowest levels that best
represents the system.
Just as the system is defined and developed throughout its life cycle, so
is the WBS. The WBS will be developed and maintained based on the
systems engineering efforts throughout the systemís life cycle. After the
Program WBS has been approved (through the CCDR process), the contractor
should then extend the Contract WBS to appropriate lower levels, to better
define the complete contract scope. When integrated with the Program
WBS, the extended Contract WBS forms a complete WBS, which will be used
throughout the programís life cycle. Figure 1-2 displays this
FIGURE 1-2. WBS