1. A building society has a long history of implementing computer-based information systems to support the work of its branches. It uses a proprietary structured systems analysis and design method. It has been decided to create a computer model of the property market. This would attempt for example to calculate the effect of changes of interest rates on house values. There is some concern that the usual methodology used for IS development would not be appropriate for the new project.
(a) Why might there be this concern and what alternative approaches should be considered?
With traditional business systems analysis there is usually an existing office procedure that managers are hoping to streamline in some way. There are people who understand the details of the jobs currently done. They can help the analyst draw up precise requirements to be met. There is, in short, a well-defined clerical equivalent of the application that is to be built.
With a computer model of the property market there is probably no equivalent of a well-defined clerical model. The analysts will therefore have to seek ideas about the working of such a model from a variety of sources. Experts, such as experienced estate agents, may be able to contribute observations, but these are likely to be fragmentary rules of thumb. The academic literature on economic modeling might be studied. In the end the analysts will probably have to resort to building a prototype of the model. They will then trial this to see if it behaves in a similar way to the property market. There is always the chance that the property market behaves in just too complex and inconsistent manner for a computer model to mimic accurately.
All this suggests that the ‘traditional’ IS development approach based on a waterfall framework would be unsuitable. A more iterative prototyping approach is sensible.
(b)Outline a plan for the development of the system which illustrates the application of your preferred methodology for this project.
- Define objectives: What does the management of the organization want from the model?
- Survey existing software solutions and the literature on the subject. Has anyone done this already?
- Consult experts. JAD (joint application development) sessions are mentioned in text as one possible approach. There are many other techniques to elicit relevant knowledge from domain experts which should be considered.
- Based on the above draw up an initial prototype design.
- Build prototype.
- Test it, probably using real data from the recent past; you can compare the results of the model with what actually happened.
- Analyze the causes of discrepancies; modify the model and rerun.
- Stop this cycle when you run out of time, or are not getting significant improvements.
- Carry out a general validation of how accurate the model it is, how easy it is to use.