Design Rationale for Increasing Profitability of Interactive Systems Development

Abstract

User-centred development (Norman & Draper, 1986; Vredenburg, Isensee, & Righi, 2001) processes advocate the use of participatory design activities, end-user evaluations, and brainstorming in the early phases of development. Such approaches work in opposition of some software-engineering techniques that promote iterative development processes such as in agile processes (Beck, 1999) in order to produce software as quickly and as cheaply as possible. One way of justifying the profitability of development processes promoted in the field of human-computer interaction (HCI) is to not only take into account development costs, but also to take into account costs of use, that is, costs related to employment, training, and usage errors. Gain, in terms of performance (for instance, by providing default values in the various fields of a computer form) or in reducing the impact of errors (by providing undo facilities, for instance), can only be evaluated if the actual use of the system is integrated in the computation of the development costs. These considerations are represented in Figure 1. The upper bar of Figure 1 shows that development costs (grey part and black part) are higher than the development costs of RAD (rapid application development), represented in the lower bar (grey part). The black part of the upper bar shows the additional costs directly attributed to user-centred design. User-