Like other agile models, that is a close loop where changes after the system development can still be implemented without the need to redo the whole system, is this possible for the RAD model as well?

Since I was told that in the Waterfall model, if there are changes after the development, it can only be implemented by redoing the whole system since it is a one way approach unlike agile where you can just go back to the development stage again.


After the cutover phase of the system, when it is already released for a few months, then the client decided that "hey I want this and that to be implemented I think it would make the system better with it". Can this be done immediately following the process model of the RAD and just directly proceed to construction phase, or do we need to recreate the entire RAD process from the start or the requirements planning phase?

From what I understood of Waterfall method, if a change is needed during the maintenance period or way after the system has been completed, it is a requirement to redo the entire Waterfall process and start from the start, which is very different for agile models where you can just go to the development stage to apply the necessary changes.

closed as unclear what you're asking by durron597, Ixrec, user40980, jwenting, user53019 Sep 23 '15 at 17:04

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    Unclear what help you need. Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it’s hard to tell what problem you are trying to solve or what aspect of your approach needs to be corrected or explained. See the How to Ask page for help clarifying this question. – gnat Sep 21 '15 at 11:45
  • @gnat i will provide an example – magicianiam Sep 21 '15 at 11:45
  • @gnat provided an example for better understanding – magicianiam Sep 21 '15 at 11:49

In any methodology, you can response to changes or modifications. However, some methodologies are better at responding to changes and delivering those changes at less expense (of time and/or money) to customers and users.

It sounds like you have a fundamental misunderstanding of what the difference between agile (iterative and incremental) and waterfall (sequential) models are. Even if you are following a sequential model, you don't need to redo the whole system if there are changes after development. In a traditional waterfall model, you capture your requirements up front and fix them. Then, you design those requirements and implement a solution, then test the solution, and finally release a system. The idea is that this system meets all of the needs of the customer and users. But there's still maintenance after the fact, and even in a sequential environment, you can release patches and new versions of the software. If you continue to follow a sequential model, you'll bundle up a large number of requirements at the front, and proceed sequentially through each of the other steps, ending in a release.

The iterative and incremental models focus on delivering smaller pieces of the software. These pieces are delivered quickly to the user and are used to obtain feedback and perform course corrections - identify mistakes or misunderstandings in the requirements or design. You don't fix the whole set of requirements for the product at the start, but instead prioritize and either demonstrate or deliver the things that will add the most value earlier in the project. This type of approach takes the mindset that software can continually evolve and change, and a project isn't done until the customers and/or users are satisfied.

Specifically, in RAD, if you get a change after Cutover, you'll have to do some level of Requirements Planning. You can't just go and implement a change (in most projects, especially larger, corporate projects). You'll need to ensure that any changes make sense within the product/project scope and constraints and that the requirements are clear and consistent. You also want to ensure that changes made for one stakeholder don't have negative impacts on other stakeholders. Most of the change effort should be in the User Design and Construction, though, and then you proceed to Cutover.

  • i see, thank you for that explanation. so in the case of RAD if a change is required in the maintenance phase of the system it is still possible to perform that change by just proceeding directly to the development phase and release phase if the result is satisfactory for the customer/client. also would you mind looking at my other question: programmers.stackexchange.com/questions/297740/… thank you – magicianiam Sep 21 '15 at 12:29
  • @magicianiam I just edited a RAD specific flow into the answer. – Thomas Owens Sep 21 '15 at 12:37
  • so it is just like waterfall where changes after the system deployment will still require you to start from the start of the model again to review the necessary changes, though their difference lies in the development stage, where in RAD changes can occur unlike in waterfall where the requirements are already set and thus changes in the requirements cant occur in the development stage. Can you provide me with links where I can understand RAD easily as i still am a bit confuse on its entire process. thank you once again, and i hope you will look into my other question about the RAD model – magicianiam Sep 21 '15 at 12:42

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