Software Engineering

9.1.3 
Adjusting project milestones
The software development schedule should be viewed as a continuum of time 
in which the software product evolves from concept to operational product. 
Development milestones represent significant decision points in the product 
evolution as it transitions from one phase of development to another. At each mile-
stone, the technical accomplishments should be reviewed to ensure that the product 
development is progressing suitably toward achieving project objectives. Milestones 
represent a hiatus from technical work to determine if the current product definition 
is sufficiently complete to justify the initiation of the next phase of development.
The objectives of each phase may be impacted by change proposals that have 
been authorized. Project milestones should not be delayed by change requests 
unless the number of changes is deemed excessive. The status of incorporating 
each change request into the software architecture should be reviewed at each mile-
stone to understand the estimated time to complete the effort. This will result in 
a delay with milestone completion, and the criteria for completing the milestone 
should be revised to reflect the need to complete the incorporation of authorized 
change requests into the software architecture. This effectively extends the planned 
development phase completion date past the milestone review. 
Figure 9.1
 shows 
the planned phase-dependent schedule and milestones and the impact authorizing 
change requests may have on completion criteria.
The relationship between phase completion dates and the associated milestone 
reviews causes confusion whenever delays occur. Each phase of development is 
planned by establishing the start data, duration, and planned completion date. A set 
of criteria must be established to determine when a phase is deemed to be complete. 
The milestone reviews are typically aligned with the end dates of each phase to per-
mit the technical review of the progress of the development effort. These reviews 
are intended to represent program decision points on whether the project should 

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