Anyone trying to pursue a career in business analysis must have heard of terms such as waterfall, agile, scrum etc. These software development lifecycles are named differently since the method adopted to reach the solution is significantly different from one another. The phases of the lifecycle are essentially more or less the same in each of these distinct methodologies. So, the important question to ask is that if the phases of the lifecycle is same then what is the need to name the lifecycles different? What do these names mean to me as business analyst? What are the things I need to do different if the phases of the lifecycle are essentially similar?
To begin with each lifecycle has requirement analysis, software design, implementation, verification, and maintenance phases. What essentially differs is the way these steps are executed in each lifecycle. Let’s talk a little bit about the waterfall methodology. It is one of the most conventional ways of building the software. It is a sequential design process where each of the phases from requirement analysis through the implementation are completed before the next phase can begin. The sequential phases have least or minimal, if any, overlap or ‘splashing’ back of the waves. The waterfall methodology works pretty well for any project that is six months or shorter. Well by this I do not mean if the project is of longer duration then waterfall methodology cannot be applied to the software development. It’s important to understand that a longer duration project will also have myriad of requirements that will change over the time. So when the solution eventually comes out, there is a high probability that most of the requirements might have changed. In contrast to this methodology are incremental methodologies. The incremental methodology can also be iterative. Now what is the stark difference between the incremental and incremental and iterative methodologies?
The incremental methodology of doing work can essentially be better understood as several water fall’s clubbed together. By this I mean that the project is divided into small increments. So the requirement analysis, design, implementation, verification or testing is done for each small increment of the project and then the team proceeds to the next. Important thing to note here is that all the requirements are gathered before any of the smaller increments start. Whereas the iterative cycle are a style where the software is developed in increments over short iterations and this gives a lot of scope to accommodate the changes that are part and parcel of any kind of project. The requirements are gathered only just before the iteration they are being developed in. With this lifecycle the chances of making faulty assumptions is very minimal. It is currently most preferred lifecycle owing to the unique characteristic of having a working software at all times of each iteration. There are multiple variations of this methodology otherwise also known as Agile such as Kanban, scrum, dynamic systems development. There are several other lifecycle methodologies as well such as code and fix, adaptive, incremental and iterative, evolutionary.
Refer to the IIBA BABOK Guide for detailed information on SDLC lifecycles.