James Pratt

Using the SUS to Help Demonstrate Usability’s Value to Business Goals

As part of an effort to connect results of human factors testing with the needs of internal business clients, a usability testing program was created for smartphones to establish a link between usability metrics and business indicators of success in the marketplace. In addition to standard usability metrics of effectiveness, efficiency, and satisfaction (ISO, 1998), a measure of hedonics (Hassenzahl, Beu, and Burmester, 2001) was used. Of particular note was the use of the System Usability Scale (SUS) (Brooke, 1996) to provide a single measure of user satisfaction for all smartphones tested. Data from 54 studies involving 872 participants were analyzed to determine if usability metrics predicted marketplace outcomes. Results show that usability metrics are significantly correlated with indicators of business success and that the SUS accounted for most of usability’s contribution. Discussion of these results, the value of SUS, and implications for usability professionals are discussed.

Training and Individual Difference Effects on the Ability to Visually Discriminate Serially Presented Graphics: Short Term Memory Capacity in Analytic and Holistic Cognitive Styles

Participants were screened for individual differences in short term memory (STM) capacity (high, low) and cognitive style (analytic, holistic) before beginning a serially-presented visual discrimination task. Participants were trained with either easy or difficult discriminations, then were transferred to novel discriminations. Variables were measured on a continuum, then dichotomized for analysis of variance. Cognitive style did not correlate with STM capacity. The two individual difference measures interacted, however, to affect accuracy performance on the transfer session of the discrimination task. Results suggest that individual differences in cognitive ability and cognitive style are orthogonal constructs that interact to affect skill acquisition and strategy development for visual-spatial tasks. Implications related to discrimination training and computer interface design are discussed.