Now that I’ve got your attention…… This has nothing to do with free drink. It’s about the pros and cons of the spiral model. Sorry to disappoint. Anyway, for those of you that continue to read this, the spiral model of systems development is a traditional method. It can be divided into four main steps which reoccur in a continuous spiral-like manner as illustrated below:
These steps or phases are Planning, Risk Analysis, Engineering and Evaluation. In the initial phase, planning, the objectives the system is expected to achieve are defined along with alternatives and their constraints.
The second phase, risk analysis, refers to the appraisal of alternatives with regard to the aims and restrictions involved as well as calculating the risks entailed in each. A risk resolution is drawn up also.
In the engineering phase the system is essentially developed and verified before moving onto the evaluation phase.
Evaluation deals with planning the next phase which is vital to the spiral model as it is a continuous system. This stage allows systems analysts to assess the system to date and see if the requirements of the end users could be satisfied better.
The spiral model is lauded by many for the advantages it provides. It often highlights precarious risks early on which can result in serious cost saving for a firm. After all, the majority of failed information systems end up exceeding their original expected budget. This allows firms to terminate a project and keep it from draining further resources.
Another advantage is that users are given access to prototypes early which again prevents some issues from going undetected for long periods of time and also helps to ensure that the system meets the desired requirements.
Regular input from the start allows systems analysts to supply a system which operates adequately. It is advantageous too that the users are so integral to the development of the system.
This being said, the model does have its flaws. As the diagram above shows, the model is complex and intricate can sometimes cause much confusion in its development. Not only that but a considerable degree of proficiency may be needed to carry out risk assessment.
The time taken to assess risks, decide upon objectives, alter objectives if necessary and create a prototype can often be unwarranted, especially for small-scale operations.
Additional problems have been known to occur in relation to the actual delineation of objectives and it may be difficult to determine measurable milestones.
Finally, the nature of the spiral model means that it could theoretically go on forever as it has no explicit end-point.
All in all, the spiral model offers a very up-to-date product with several early indicators to help avoid unnecessary use of resources however it does have its failings when it comes to clarity and time consumption.
Thanks for reading if you stuck it out.