Testing
System Usability Scale (SUS) Administration & Scoring
The System Usability Scale (SUS) is a quick way to measure perceived usability. First, participants complete the SUS questionnaire after using a product. Then, you calculate individual and average SUS scores. Finally, compare scores against industry benchmarks to understand relative usability.
Duration
1 hour
Group Size
4-8
Category
Testing
Difficulty
Easy
Participants will be able to administer the SUS questionnaire, calculate SUS scores, and interpret results against industry benchmarks.
Participants will produce a SUS score, quantitative usability data, and benchmarkable results.
SUS is quick, validated, and benchmarkable. Compare your product's score to others for context. A score of 72 is above average.
Avoid these mistakes: Changing the wording invalidates results. The questions are intentionally awkward. Small sample sizes (under 12-14 participants) produce unreliable scores. Don't use SUS on prototypes; users need real experience.
The alternating pattern (positive/negative statements) ensures respondents read each question, but scoring is tedious. Accept it.
Use SUS after usability testing to quantify issue severity, before/after redesigns to measure improvement, and periodically to track trends.
Pair SUS with qualitative data. SUS tells you how good/bad; usability testing tells you why. The score benchmarks; observations suggest fixes.
When reporting to stakeholders, start with the letter grade (A-F) from the curved scale. Then share the numeric score for detail.
Avoid these mistakes: Changing the wording invalidates results. The questions are intentionally awkward. Small sample sizes (under 12-14 participants) produce unreliable scores. Don't use SUS on prototypes; users need real experience.
The alternating pattern (positive/negative statements) ensures respondents read each question, but scoring is tedious. Accept it.
Use SUS after usability testing to quantify issue severity, before/after redesigns to measure improvement, and periodically to track trends.
Pair SUS with qualitative data. SUS tells you how good/bad; usability testing tells you why. The score benchmarks; observations suggest fixes.
When reporting to stakeholders, start with the letter grade (A-F) from the curved scale. Then share the numeric score for detail.
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