Can the System Be Improved?

Abstract

The preceding three chapters have focused on formative evaluation, the assessment of the system as part of the overall iterative design process (as described in Chapter 5). The main point of this evaluation is to find out about the design of the system during its development, in order to address those aspects that need modification and revision. This will allow changes to be made before product release. In contrast, summative evaluation takes place when the system or product has moved from being experimental to operational, and is usually carried out towards the end of the design life cycle. Consequently, the broad difference between formative and summative evaluation concerns the nature of the purpose. Formative evaluation (as implied by the term) is carried out to help the system designer refine and ‘form’ the design, while summative evaluation is concerned with the overall performance of the system. Hewett (1986) defines summative evaluation as follows: ‘Summative evaluation involves assessing the impact, usability and effectiveness of the system - the overall performance of User and system.’ Implicit here is the suggestion that the system or product is close to being launched.