The Role of the Precedence Diagram

From the RBS, the team can develop the precedence diagram at the function or at the feature level. This shows how functions or features are dependent upon one another as either predecessors or successors. The objective here is to decide on groupings of functions/features in the successive increments of the Staged Delivery approach or the Feature-Driven Development approach. The next two subsections take a quick look at each approach and how the precedence diagrams can be used.

In the Staged Delivery Waterfall Model

Because each successive stage is dependent upon all previous stages, it is necessary that all precedence relationships be preserved. That is, whatever functions/features are needed to build the current stage deliverables will have been built in some preceding stage. In practice this is easier said than done, especially in larger projects, where some dependencies are so elusive that they can be discovered only during testing.

In the Feature-Driven Development Model

For this approach you find the precedence diagram serving another role. Feature sets are groupings of features based on technical relationships. Furthermore, the feature sets should be defined with minimal coupling and maximum cohesion in mind. This is critical because the building and testing of feature sets can occur concurrently as well as sequentially. Ideally each feature set would be independent of any other feature set, and the problem would go away. But that does ...

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