No need to read: Developing a pictorial single-item scale for measuring perceived usability

To facilitate the measurement of perceived usability in product evaluation, we have developed a one-item pictorial scale called PSIUS (Pictorial Single-Item Usability Scale), which aims to measure the satisfaction component of the usability construct. This bipolar scale consists of three main visual elements: satisfaction with the system, emotions experienced during system use and system to be evaluated. Employing a user-centred iterative design process, the scale was tested in two validation studies (N = 60; N = 38) using student participants. Sensitivity, convergent validity, divergent validity and criterion-related validity of the scale were determined. The results showed that satisfactory convergent validity was achieved, with the pictorial scale showing strong correlations with sum scores of established usability scales such as the System Usability Scale (SUS) and the Post Study System Usability Questionnaire (PSSUQ). The other validity coefficients also showed overall positive results, suggesting that the development of the pictorial scale may be a promising endeavour. The PSIUS represents an initial attempt to provide a nonverbal approach to the summative evaluation of technical systems.