T20: Using the System Usability Scale

Tuesday, 17 July 2018, 13:30 – 17:30


James R. Lewis (short bio)

IBM Corporation, United States



Standardized usability questionnaires are questionnaires designed for the assessment of perceived usability, typically with a specific set of questions presented in a specified order using a specified format with specific rules for producing scores based on the answers of respondents. The System Usability Scale (SUS) is the most widely-used questionnaire for the assessment of perceived usability.

The purpose of this course is to provide an introduction to the SUS.  This introduction will include background on standardized usability measurement, where the SUS came from, the research supporting its use as a measure of perceived usability in research and applied UX work, and how to analyze SUS data.

At the end of the course, attendees will know the history of the SUS, how to use it in current work, and where future research is likely to go.

Content and Benefits:

The course starts with coverage of the basic psychometric properties of standardized measurement – reliability, validity, and sensitivity. The next topic is the inventory of post-study questionnaires (such as the QUIS, SUMI, PSSUQ/CSUQ, SUS, and, most recently, UMUX and UMUX-LITE) – descriptions of the instruments, summaries of their known psychometric properties, and key recent research findings. This leads into an extended discussion of the SUS due to the relatively large amount of normative and usage data that has become available for it in the past ten years, including the history of the SUS, how to analyze SUS data (including numerous quantitative exercises), and the future of the SUS.  After completing this course, attendees will have a firm foundation in why and how to use the SUS.

  1. Introduction to standardized usability measurement
    1. What is usability?
    2. What is a standardized questionnaire?
    3. Advantages of standardized usability questionnaires
    4. What standardized usability questionnaires are available?
    5. Assessing the quality of standardized questionnaires
  2. The history of the SUS
    1. Where did the SUS come from?
    2. What research supports the use of the SUS as a measure of perceived usability?
  3. How to use the SUS
    1. Basic statistical review
    2. Comparing SUS scores (including quantitative exercises)
    3. Computing confidence intervals (including quantitative exercises)
    4. Interpreting SUS scores (including quantitative exercises)
    5. Working with special SUS analyses (including quantitative exercises)
  4. The future of the SUS
    1. Research
    2. Practice
  5. Wrapping up


Target Audience:

The course will likely be of interest to a wide variety of attendees, but will be especially useful to those usability practitioners and HCI researchers who currently use or plan to use the System Usability Scale or other standardized usability questionnaires. Attendees should bring computers with spreadsheet software to work through the quantitative exercises.

Bio Sketch of Presenter:

Dr. James R. (Jim) Lewis, Ph.D., CHFP
James R. (Jim) Lewis graduated with an M.A. in Engineering Psychology in 1982 from New Mexico State University, and received his Ph.D. in Experimental Psychology (Psycholinguistics) from Florida Atlantic University in 1996. He has worked as a human factors engineer and usability practitioner at IBM since 1981. He has published influential research on the measurement of perceived usability, use of confidence intervals, and sample size estimation for usability studies. He is co-editor in chief of the Journal of Usability Studies, on the editorial boards of the International Journal of Human-Computer Interaction and Voice Interaction Design, and wrote the chapter on usability testing for the 3rd and 4th editions of the Handbook of Human Factors and Ergonomics (2006/2012). He is the author of "Practical Speech User Interface Design" (2011) and co-author (with Jeff Sauro) of "Quantifying the User Experience" (2012/2016). He is a BCPE Certified Human Factors Professional, an IBM Master Inventor with 91 US patents issued to date, a member of the Human Factors and Ergonomics Society, and a member and past-president of the Association for Voice Interaction Design.