A software lifecycle is a model that describes all the activities that go into creating a software product. Product development styles vary tremendously among different kinds of projects, requiring different kinds of tasks and different task orderings. Choice of the wrong lifecycle model can result in missing tasks and inappropriate task ordering, which undercuts project planning and efficiency. Choice of an appropriate lifecycle model has the opposite effect—ensuring that all effort is used efficiently. Every project uses a lifecycle of one kind or another—explicitly or implicitly—and this practice ensures that the choice is made explicitly and to maximum advantage.

Efficacy

Major Risks

Major Interactions and Trade-Offs

None

The summary entries in the table describe only the effect of explicitly choosing a lifecycle model. In addition to those effects, the specific lifecycle model chosen will also have greater or lesser ability to reduce schedule, improve progress visibility, and affect risk level. For more on lifecycle model selection, see Chapter 7, Chapter 7.