Psychometric Properties of the Persian Language Version of the System Usability Scale

Background: The System Usability Scale (SUS) is a widely used self– administered instrument for evaluating the usability of a wide range of products and services. The aims of this descriptive-methodological study were to develop and investigate the psychometric properties of the Iranian version of the SUS. Methods: The study was conducted among 202 university students from the Tabriz University of Medical Sciences, Iran. Content validity was evaluated by a panel of 10 experts. Construct validity was assessed by exploratory and confirmatory factor analyses. The internal consistency and test-retest reliability were assessed by Cronbach’s alpha and Intraclass Correlation Coefficient (ICC), respectively. Additionally the feasibility of the measure was judged by ceiling and floor effect. Results: Content validity of the short form of Iranian SUS was established. Factor analyses supported the conceptual uni-dimensionality, and thus confirmed the construct validity of the measure. The internal consistency (? = 0.79) and test retest reliability (ICC = 0.96) were both approved and there was also no ceiling nor floor effect. Conclusions: The findings support the use of SUS for both practical and research settings in Iranian population.