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

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. 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. 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 (α = 0.79) and test retest reliability (ICC = 0.96) were both approved and there was also no ceiling nor floor effect. The findings support the use of SUS for both practical and research settings in Iranian population.