SUS stands for System Usability Scale. SUS was developed by Brooke (1996) as ”the quick and dirty” assessment tool – it was used to quickly and cheaply assess a product or a service. (1). A low cost usability test.
A SUS test is supposed to cover:
- Effectiveness (the ability of users to complete tasks).
- Efficiency (how difficult it was to perform the task).
- Satisfaction (how the users felt when performing the task).
A system can be a car, a website or a product. SUS assessment has a reliability value of 0.85 (2).
A SUS assessment is constructed of 10 statements that are valued on a 5 point scale, according to how much the user agrees or disagrees with the statement. The result can vary between 0 and 100, where a higher score indicates better usability. Every other question is a positive statement and every other question is a negative statement, so both the user and the person analyzing the result have to stay focused!