Estimating Sample Size for Usability Testing

Authors

  • Alex Cazañas University of Queensland, Brisbane
  • Andre de San Miguel University of Queensland, Brisbane
  • Esther Parra Escuela Politécnica Naciona

DOI:

https://doi.org/10.29019/enfoqueute.v8n1.126

Keywords:

usability testing, problem discovery, sample size

Abstract

One strategy used to assure that an interface meets user requirements is to conduct usability testing. When conducting such testing one of the unknowns is sample size. Since extensive testing is costly, minimizing the number of participants can contribute greatly to successful resource management of a project. Even though a significant number of models have been proposed to estimate sample size in usability testing, there is still not consensus on the optimal size. Several studies claim that 3 to 5 users suffice to uncover 80% of problems in a software interface. However, many other studies challenge this assertion. This study analyzed data collected from the user testing of a web application to verify the rule of thumb, commonly known as the “magic number 5”. The outcomes of the analysis showed that the 5-user rule significantly underestimates the required sample size to achieve reasonable levels of problem detection.

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References

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Published

2017-02-24

How to Cite

Cazañas, A., de San Miguel, A., & Parra, E. (2017). Estimating Sample Size for Usability Testing. Enfoque UTE, 8(1), pp. 172–185. https://doi.org/10.29019/enfoqueute.v8n1.126

Issue

Vol. 8 No. 1 (2017): INCISCOS 2016, Special Edition

Section

Miscellaneous

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