Prescriptive Process Models strive for structure and order in software development. They tend to occur sequentially with defined guidelines, however they may not be the most effective for changing systems.
Waterfall
The waterfall method, sometimes called the classic life cycle, is one of the best known prescriptive process models. Each step move you forward and down from Communication to Deployment.
In Communication you have project initiation and requirements gathering, in Planning you have the process of estimating, scheduling, and initializing tracking, and so on. See Fig 4.1 for more details.
Rarely does a real world project move forward in such a sequential process. More often it is a process of changes and going back and forth. Another issue is since you can’t move to the next step until the current process is finished, you might have some people who are waiting on others to finish – i.e. being blocked.
The V-Model
The V Model has a tendency to move items forward, but you can go back to previous steps because rarely can you move always forward in a sequential pattern.
Incremental Models
Similar to the sequential and the parallel methods, different groups start at different times, and progress at their own pace so the software is developed in increments.
Different parts of the project are completed at different times, so if the final project cannot be completed, still part of it can be, and that part will be fully functional.
Evolutionary Models
Evolutionary Models, like the spiral method, work on continual improvements to an existing software. They proceed to improve each iteration to get closer to what the customer/client wants.
Each set allows for all of the steps, however, it moves the project forward from where it is toward a final completed goal.
Allows for changes are new requirements come in, as rarely will you have all of the requirements up front, especially for large projects.
Prescriptive Process Models was originally found on Access 2 Learn
