This metric do not tell us why users struggle with a design, nor do they provide direct insights as to how we can improve it. They simply are a way of keeping track of how the users feel about the experience of using a product or service. Pros
- Have a free normed database of scores.
- The biggest advantage to using the SUS is that it's such an old scale that there is a large amount of industry-wide data available to help benchmark your score and understand it in the context of your peers and competitors
- SUS correlates strongly with a much simpler metric, the single-question Net Promoter Score;
- SUS is considered a technology-agnostic questionnaire, meaning the items aren't specific to any technology or platform.
- Complex scoring method promising to mistakes because a 0–100 score is not equivalent to a percentage score;
- To score the SUS, follow these steps:
- For odd items, subtract 1 from the user response.
- For even-numbered items, subtract the user responses from 5. This scales all values from 0 to 4 (with 4 being the most positive response).
- Add up the converted responses for each user and multiply that total by 2.5. This converts the range of possible values from 0 to 100 instead of from 0 to 40.
- Average together the scores for all participants
- User impressions of the experience as a whole are subject to the peak-end effect (that is, the most intense and last parts of the experience, either positive or negative, impact participants' recollections and evaluations the most);
- it doesn't address usefulness or utility.