3.1 What is a successful system?

achieved what was intended of it

This implies that the requirements for the system were identified accurately and translated into stated and agreed objectives before the system was developed and that it is possible to measure performance of the system against these objectives in order to check they have been met.

… it was operational at the time and cost that was planned

Here it is assumed that there was an agreed and approved development plan that included timescales and costs and that performance against this plan can be measured. It also assumes that it is clear what ‘operational’ means and it is possible to be certain when it has been achieved.

An important difference between these first two parts of the definition is that the first one is about the success of the system and the second one is concerned with the success of the project that built the system. For an individual project, judgments of success are not necessarily the same across both aspects. A project regarded as well-managed may fail to deliver the intended outcomes whilst a project that experiences many problems can still be capable of delivering success, though almost always at a price. There does tend to be a positive correlation between the quality of the project management and the quality of the output, but there are exceptions.

… the project team and the users are pleased with the result

This is where the definition becomes even murkier with a number of potentially conflicting judgements. First, there is the relative importance of the views of the project team and the users. Some would regard the views of the professionals who make up a project team as paramount but others would say that the views of the project team are largely irrelevant as long as the users are content. The next big question it raises is ‘who are the users?’ Are the users just the people who interact directly with the system or do they include those who may not know it exists but are users of the services it supports? Are all users’ views equally important, and what about the views of the client or customer? This part of the definition also implies that ‘pleasure’ can be measured or assessed.

… and they continue to be satisfied afterwards.

This shares the problems of the previous phrase. Who are the users whose degree of satisfaction should be considered later? Another question is how long a period of time is covered by ‘afterwards’. They may not be the original users, however defined. Measuring and/or assessing satisfaction is also an issue here. Should the same criteria be used as when the system was new or might there be a different set of standards now that users are familiar with the system? Another issue is what allowances should be made for the passage of time. For example, the environment may have changed to such an extent that there is now a need for the system to do things that were not envisaged when the system was designed.