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Refining the Test Phase of Usability Evaluation: How Many Subjects Is Enough?
Abstract
Attention has been given to making user interface design and testing less costly so that it might be more easily incorporated into the product development life cycle. Three experiments are reported in this paper that relate the proportion of usability problems identified in an evaluation to the number of subjects participating in that study. The basic findings are that (a) 80% of the usability problems are detected with four or five subjects, (b) additional subjects are less and less likely to reveal new information, and (c) the most severe usability problems are likely to have been detected in the first few subjects. Ramifications for the practice of human factors are discussed as they relate to the type of usability test cycle employed and the goals of the usability test.
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Cited by
A mathematical model of the finding of usability problems
Nielsen, J., & Landauer, T. K. (1993) · Proceedings of the SIGCHI conference on Human factors in computing systems - CHI '93 · doi:10.1145/169059.169166 · Cited by 1,961
Beyond the five-user assumption: benefits of increased sample sizes in usability testing
Faulkner, L. (2003) · Behavior Research Methods, Instruments, & Computers · doi:10.3758/bf03195514 · Cited by 1,053
van den Haak, M., De Jong, M., & Jan Schellens, P. (2003) · Behaviour & Information Technology · doi:10.1080/0044929031000 · Cited by 486
Number of people required for usability evaluation: the 10±2 rule
Hwang, W., & Salvendy, G. (2010) · Communications of the ACM · doi:10.1145/1735223.1735255 · Cited by 410
Sample sizes for usability studies: Additional considerations
Lewis, J. R. (1994) · Human Factors: The Journal of the Human Factors and Ergonomics Society · doi:10.1177/001872089403600215 · Cited by 341
Metadata
- Authors
- Virzi, R. A.
- Venue
- Human Factors: The Journal of the Human Factors and Ergonomics Society
- Publisher
- SAGE Publications
- Published
- 1992-08
- Volume
- 34
- Issue
- 4
- Pages
- 457-468
- ISSN
- 0018-7208 (ISSN-L)
- 1547-8181
- OpenAlex
- W1596953637
- Cited by
- 1,190
- References
- 0
- FWCI
- 11.37
- Type
- journal article
- Language
- en
- Open access
- closed
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- Virzi, R. A. (1992). Refining the Test Phase of Usability Evaluation: How Many Subjects Is Enough? Human Factors: The Journal of the Human Factors and Ergonomics Society. https://doi.org/10.1177/001872089203400407
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Semantic Scholar’s data is described in: Kinney, R., et al. (2023). The Semantic Scholar Open Data Platform. arXiv:2301.10140.
