By Jamie, James and Chloe The Spiral Model By Jamie, James and Chloe

Key Principles Was defined by Barry Boeham in 1985. Uses elements of waterfall and prototype models. Can have any amount of loops, therefore improving and changing until the requirements are met. Mostly used in large projects.

Advantages Flexible. Reduces risks. It can make the management of large projects simpler. It will be reviewed frequently by each of the four quadrants therefore fixing problems found. Therefore making the process less prone to failure. Changes can be made at any stage of the lifecycle, also coping with changes is not very hard to manage. Costs are easier to predict. A good final product because of all the review and fixing opportunities.

Disadvantages Cost is usually higher using this method. Complicated approach especially if the goals are known and have a clear SRS. This method requires specialist knowledge to implement into a project. Sticking to the SRS can sometimes be difficult and if not done then the can not work as well as other methods. Not suitable for low risk projects.

References http://www.ianswer4u.com/2011/12/spiral-model-advantages-and.html#axzz2ebTeMGQh http://en.wikipedia.org/wiki/Spiral_model