Abstract

Usability Evaluation measures remain too close to what were originally dependent variables in factorial experiments. The basis for genuine ‘usability problems’ in such variables is not guaranteed, but there has been little progress on finding replacements since HCI’s shift from the laboratory to field studies. As a result, the worth of much usability evaluation is questionable. Such doubts will persist until we can fully align the purpose of evaluation with the purpose of design, which is to create value in the world through innovative products and services, whether sold in markets, or provided free by either individuals or public and voluntary agencies. This chapter reviews issues with common usability measures and introduces a framework that can plausibly re-align evaluation criteria with design purpose by adapting an approach from consumer psychology. This provides opportunities to deploy evaluation measures and instruments that meet the needs of design, rather than reflect skill sets from psychology and human factors. The current gap between design and usability evaluation narrows, but an exclusive usability focus in evaluation becomes impossible. Instead, the role of usability in delivering or degrading intended worth is placed in a wider worth systems context. The maturity of usability will thus be evidenced by its effective integration with a range of design and evaluation concerns. It can longer assume intrinsic importance, but has to demonstrate it in the context of achieved product value.