Value enabling interaction mediates between design and evaluation
Gilbert Cockton · Northumbria Research Link (Northumbria University) · 2004
The interplay between usability evaluation and user interface design is indirect and must be mediated by value enabling interaction. We do not evaluate systems in HCI, we evaluate interaction. We thus cannot evaluate designs, but only their consequences for the quality of interactions. In evaluating interaction, we anticipate or observe user difficulties. A design may or may not contain the potential causes of a user difficulty. Causes have to be inferred from user difficulties in context. There is thus no direct interplay in either direction, either from design to evaluation, or from evaluation to design. Instead, both are mediated by interaction, but even this mediation is not direct. We must reason from designs to interactions, and from interactions to design features as causal factors. However, these processes are inherently descriptive. The role of evaluation must go beyond description to judgement, since the literal meaning of “evaluation” is to (bring) out value, that is, to find it in one place and to express it somewhere else. In HCI, we find value in interaction, but we judge value in the world. Until we start by stating the intended value of digital products, HCI can not reach the end point of delivering computer systems that are worth using. The relationship between design and evaluation is thus mediated by user interactions that do (not) deliver intended value.