Psychometric Evaluation of the PSSUQ Using Data from Five Years of Usability Studies

Abstract

Factor analysis of Post Study System Usability Questionnaire (PSSUQ) data from 5 years of usability studies (with a heavy emphasis on speech dictation systems) indicated a 3-factor structure consistent with that initially described 10 years ago: factors for System Usefulness, Information Quality, and Interface Quality. Estimated reliabilities (ranging from .83-.96) were also consistent with earlier estimates. Analyses of variance indicated that variables such as the study, developer, stage of development, type of product, and type of evaluation significantly affected PSSUQ scores. Other variables, such as gender and completeness of responses to the questionnaire, did not. Norms derived from this data correlated strongly with norms derived from the original PSSUQ data. The similarity of psychometric properties between the original and this PSSUQ data, despite the passage of time and differences in the types of systems studied, provide evidence of significant generalizability for the questionnaire, supporting its use by practitioners for measuring participant satisfaction with the usability of tested systems.