Quantitative usability assessment relying on experiential and specific task based SUS ratings

Abstract

This study has two main objectives; one is to present the empirical result that shows how the SUS scores vary when end-users perform usability assessment relying on experience and by executing the assigned list of specific tasks on academic websites. The results are obtained by using independent sample t-test that scrutinizes the slight but significant difference in mean SUS scores among two. Results also investigate that 85.29% of websites have shown higher mean SUS scores when usability assessment is conducted with the assigned list of specific tasks whereas only 14.70% of websites have shown higher mean SUS scores when usability assessment is performed based on the experience. Another aim is to determine the relationship which is found to be strong positive correlation between system effectiveness, an ISO metric, measured as task success rate and subjective usability scores, measured through System Usability Scale (SUS) for 50-academic websites. It concludes that successful completion of the tasks results in high usability scores.