System Usability Scale Validation from The Expert Perspective

Abstract

The System Usability Scale (SUS) is a well-known method for quickly evaluating usability. Although SUS corresponds more strongly with user preference, quantitative data like SUS score is challenging to express in absolute terms. Therefore, the research aims to explore the validity of SUS evaluation results of an e-budgeting system from the expert perspective. With a comparative study approach, the research compared each of the 10 SUS indicators’ scores with the result of the qualitative usability evaluation. Data were obtained from three usability experts, who conducted Nielsen’s heuristic evaluation, the SUS measurement, and interviews. The research obtained two main findings. Firstly, no entirely valid scores of SUS indicators were found from three usability evaluations of the three usability experts. Secondly, only the score of ease of use shows significant relevance to the heuristic evaluation and interview result. Those findings may provide new insights when evaluating usability.