System Usability Score

The System Usability Score (SUS) measures how easy a system is to use, providing valuable insights for user-centered design.

System Usability Score

Welcome to our article, where we delve into the world of System Usability Score (SUS). Discover how this widely used metric can gauge the usability and effectiveness of your systems and improve user experience.

Where did System Usability Score come from?

The System Usability Score (SUS) is a widely used tool for evaluating the usability of a system or product. It was developed by John Brooke in 1986 and has since become a standard method for measuring user satisfaction. The SUS questionnaire consists of ten statements, which users rate on a five-point scale from strongly agree to strongly disagree. By calculating the average score, organizations can understand how usable their products are and make improvements based on user feedback.

What are the key concepts?

Some of the key concepts involved in System Usability Score include:

  • System Usability Score (SUS) is a widely used method for measuring the usability of software, websites, or any technological system.
  • It is a questionnaire-based approach that combines subjective ratings and objective metrics to provide a quantitative measure of usability.
  • The SUS questionnaire consists of 10 statements that users rate on a Likert scale. Their responses are then analyzed to calculate the overall SUS score.
  • The SUS score ranges from 0 to 100, with higher scores indicating better usability. It provides an overall measure as well as individual item scores for further analysis.
  • SUS can be used at different stages of product development to identify areas of improvement and compare the usability across different systems or iterations.

What's the process?

The System Usability Score (SUS) is a widely used tool to gauge the usability of software interfaces. The process typically involves administering a questionnaire to participants who have interacted with the system. The questionnaire consists of 10 standardized statements related to usability, such as ease of use and satisfaction. Participants rate each statement on a Likert scale, and their scores are then converted into a SUS score ranging from 0 to 100. This score provides an indication of the overall usability of the system, allowing organizations to identify areas for improvement and track progress over time.

What outcomes can you expect?

Some of the outcomes you can expect from working with System Usability Score are:

  • Understand the importance of measuring usability in system design and development.
  • Learn how to calculate System Usability Score (SUS) based on a set of standardized questions.
  • Gain insights into interpreting SUS scores and what they mean for overall system usability.
  • Discover ways to use SUS as a benchmarking tool for comparing different systems or iterations.
  • Identify areas for improvement and prioritize usability enhancements based on SUS feedback.

Are there any debates or criticisms to be aware of?

  • Standardizing the calculation of System Usability Score (SUS) has been debated, with critics arguing for alternative scoring approaches.
  • SUS is limited in measuring subjective experiences and emotions, making it less comprehensive for evaluating user satisfaction.
  • Some critics argue that SUS scores can be influenced by factors such as familiarity bias and social desirability bias.
  • There is a lack of consensus on the optimal scale used in SUS, with researchers exploring alternatives to the traditional 0-100 range.
  • The use of SUS alone may not provide a complete picture of system usability, as it does not capture specific task performance metrics.


The System Usability Score (SUS) is a widely used tool for evaluating the usability of a system or product. It provides organizations with a quantitative measure of user satisfaction and helps identify areas for improvement. While there are limitations to its use, such as subjective bias, SUS remains an effective benchmarking tool in assessing overall system usability. By incorporating SUS feedback into the design and development process, organizations can make informed decisions to enhance user experience and ensure the success of their products.


  • System Usability Score (SUS) is a reliable tool for evaluating the usability of a system or product.
  • SUS provides a standardized and quantitative measure of usability, allowing for easy comparisons between different systems.
  • The 0-100 scale used by SUS makes it simple to understand and interpret the results.
  • By assessing both effectiveness and satisfaction, SUS captures the overall user experience with a system.
  • However, interpreting SUS scores requires considering various factors such as user expectations and context.


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