Information System Development or ISD is the focus on the steps and approach a designer will take when creating a new software project, ISD’s outline the simple methodologies used with diagram approaches each specialising in what the development type is. The use of ISD’s usually revolves around a cycle or steps that the designer will take when creating the project, usually they will start off slow and move up to more complicated matters. Two of the most commonly used ISD’ Models are the Spiral and Waterfall diagrams, each of the diagrams have beneficial features which depend on the content of the designing project.
The first of these models I will discuss is the Waterfall model. This is a linear and sequential approach to the designing process, the method defines specific targets for each stage in the cycle often this system is adopted by those working towards a strict deadline and once that one part of the cycle has been completed it cannot be revisited and the designer must press on to the next stage for the project. This is one of the main advantages to this approach as there are loads of tasks to be handled and the designer will have to organize and set deadlines for each of the tasks that must be done and completed so that they can move on to their next stage in time and essentially meet their target deadline. The problem with this approach is that it always moves towards a specific goal and finalized project so it cannot be used for one that has to be re-edited and constantly updated such as a blog like this. Here you can see an example of the Waterfall model:
The Spiral Model is completely different from the Waterfall one, created by Boehm in 1988 the model revolves around four activities, which are planning, risk assessment, engineering and evaluation. This model is based on the principal that there is no end goal or completion but only smaller goals which inevitably repeat on themselves, this model is also always being evaluated from user testing so improvements are always being made, this fits in well with projects such as blogging which the main purpose of is so information can constantly be evaluated and changed accordingly never reaching an end. This type of process is called an iterative one, unlike the waterfall method this is completely user centered basing all information and outcomes on what user feedback is. This model does have its disadvantages, as it would not be ideal for targeted projects that designers are hired to do, as they usually always have an end goal and there can be no completed date, this can closely be related to those of a website or a shopping system that does not ever get completed but always gets reformed and changed all based on user input. Here you can see an example of what the waterfall model looks like, as you can probably tell it is much more complex looking in comparison to the waterfall:
The ADDIE model is what most of these developments are based upon, this stands for Analysis, Design, Development, Implimentation and Evaluation. This is was one of the first ever design models and their has been much discussion and debated about the effectiveness of it, as you can tell from the outlines I have written above the name closely relates to both of them, with features supporting user input and evaluation and the setting of goals and targets. There are over 100 models available but many are based upon this one as it is generic, though documentation has been around that criticize the model, I found an online book from deekayen.net which said
ADDIE has been widely and often criticized for being too systematic. ADDIE is often said to be too linear, too constraining, and even too time-consuming to implement with regards to e-learning. Source: http://deekayen.net/book/export/html/762
Other popular models do exist that are still widely based on the ADDIE model, these include the modified ADDIE model, this model has been modified to run faster and more smoothly with designers knowing set goals, targets and having expectations of what the design should be able to acheive.
Another of the lesser-known models is the star model, this focuses on evaluating tasks as soon as they have been completed, which is more focused toward a user friendly system rather than one based on the designer. There is a lot of feedback processed within this model and there is no official order in which tasks are completed. Here you can see an example of the star model:
Finally, the popularity of all these models shows that there must be a clear definition of what the project is aiming for, wether it be a system that is repetatively being updated or one that is targeted to reach a specific goal. But it really comes down to user preference on how much they want to survey they end users as this is the focus of many of the models available.
Resources:
http://cadswes.colorado.edu/PDF/RiverWare/DavidsonLV2002.pdf
http://fog.ccsf.cc.ca.us/~mmalacho/OnLine/ADDIE.html
http://searchsoftwarequality.techtarget.com/sDefinition/0,,sid92_gci755347,00.html
http://searchsoftwarequality.techtarget.com/sDefinition/0,,sid92_gci519580,00.html
