Usability Sample Size Calculator
Use this calculator to generate a sample size recommendation for your usability study.
Recommended Sample Size:
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References

Faulkner, L. (2003). Beyond the five-user assumption: Benefits of increased sample sizes in usability testing. Behavior Research Methods, Instruments, & Computers, 35(3), 379-383.

Hwang, W & Salvendy, G (2010). Number of people required for usability evaluation: The 10 +- 2 rule. Communications of the ACM, 53(5), 130 - 133.

Macefield, R. (2009). How To Specify the Participant Group Size for Usability Studies: A Practitioner's Guide. Journal of Usability Studies, Volume 5, Issue 1, Nov 2009, pp. 34 – 45

Medlock, M.C., Wixon, D., Terrano, M., Romero, R., and Fulton, B. (2002). Using the RITE method to improve products: A definition and a case study. Presented at the Usability Professionals Association 2002, Orlando Florida.

Pernice, K. & Nielsen, J. (2009). Eyetracking methodology: How to conduct and evaluate usability studies using eyetracking. Fremont, CA: Nielsen Norman Group

Tullis and Albert (2008). Measuring the user experience: Collecting, analyzing, and presenting usability metrics. Boston, MA: Morgan Kaufmann.

While the majority of usability testing at Blink is conducted with small sample sizes (10-16), conducting larger studies for the right reasons is an important part of what we do. This calculator generates a usability sample size recommendation based on the key factors we use in daily practice. It is based on a review of current literature as well as Blink's experience conducting hundreds of usability studies over the years. We hope you find the tool useful.
How many different groups of users will you compare in the study (e.g., experts vs. novices)?
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5
Will each group of users be performing the same or different tasks?
Will you be comparing the results of this study against future studies to measure progress?
How many different designs will you compare in this study?
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5
How many designs will each user evaluate in this study?
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Will eye tracking be used in this study?