As we have seen in previous blogs in this category, there are many ways to develop an information system. There are the traditional methods e.g SDLC, Waterfall,Spiral and also there are Agile methods e.g XP etc.
As both SDLC and Wterfall models have been covered ….i have chosen to show how the spiral model approach to developing information systems is used.
the Spiral model was first created by Brry Boehm in 1986. the spiral model combines iterative development (prototyping) with aspects of the waterfall model. One of the major advantages of the spiral model is that is incorporates risk assesment. The four stages of the spiral model are
- Planning – setting project objectives
- Risk Analysis – analysis of alernatives and identification and solution of risks
- Engineering – equivilant to build phase of SDLC with coding and testing
- Evaluation – testing product with customers
- Project Start: this is in the 1st quadrant (blue) – determine objectives , consider alternatives and constraints.
- if project is moved on it goes into the 2nd quadrant (purple) – strategy is analysed from the viewpoint of risk and solutions to minimise these risks are investigated.
- 3rd quadrant (pink) – a solution to achieve the goals set out in first quadrant is put into place
- 4th quadrant(yellow) – The results of the risk-reduction strategies are assessed, and if all risks are resolved, the next phase is planned and started.
After each round (iteration) of the spiral model a decsion is made whether to carry on or not. This allows for mistakes and changes to be made without major disturbance and it also ensures that the project that goes forward will be the best.
there are many advantages of using this model to develop information systems …
- ability to detect high risk projects and the option of continuing or not at each iteration
- includes the best features of the both the SDLC and the prototyping approach
- adds validation of requirements and design together with risk analysis
- Users get to see and experience the system quite early because of prototyping tools
Overall the Spiral model is very good as it almost incorporates all other traditional methods e.g SDLC , Waterfall and prototyping while also having risk management built in. It is not the cheapest option however in my opinion is the best way to go when developing your own information system.