SUSscore

SUSscore refers to the numerical score produced by the System Usability Scale (SUS), a ten-item questionnaire used to assess perceived usability of a product, service, or interface. The SUS consists of ten statements presented on a five-point Likert scale (strongly disagree to strongly agree). To compute the SUS score, for odd-numbered items, subtract 1 from the respondent's rating; for even-numbered items, subtract the rating from 5. The ten item scores are summed and multiplied by 2.5 to yield a single SUS score ranging from 0 to 100.

Interpretation of the SUS score is that higher values indicate greater perceived usability. A score around 68 is commonly cited as average. Scores above 68 suggest above-average usability, with higher values indicating progressively better usability. Some sources describe qualitative bands (for example, 85 or higher as excellent, 70–85 as good), but exact thresholds can vary depending on context, sample, and language.

SUSscore is widely used in industry and research for quick usability assessment, benchmarking across products or versions, and tracking usability improvements over time. It is suitable for comparative studies and can be translated for cross-language use with appropriate validation.

Limitations include that the SUS provides a single, global usability estimate and does not identify specific issues or design flaws. It is subjective and sensitive to respondent bias, cultural factors, and the context of use. Therefore, it should be complemented with qualitative feedback, task-based measures, or more detailed usability instruments when diagnosing problems or guiding design decisions.