Development and Psychometric Validation of a Positively Worded German Version of the System Usability Scale (SUS)

Despite its popularity, knowledge of the System Usability Scale's (SUS) psychometric quality in German is limited. This article developed a positively worded German SUS version and investigated two existing versions. In a preregistered first study (N = 250), positive alternatives for negative items were evaluated using item analyses, exploratory factor analyses, and language expert suggestions. The two existing versions were also compared. A preregistered second study (N = 877) involved participants interacting with 12 websites and completing the different SUS versions to validate the new positive-only and the original versions. Analyses included item analyses, confirmatory factor analyses, correlations with related scales, and error analyses. Findings indicated that the SUS-DE-Pos, a positive version based on Rummel, performed best. Researchers should use this version or Rummel's version if negative items are needed. Overall, this work provides validated German SUS versions, with and without negative items, addressing a critical gap for German-speaking HCI researchers and practitioners.