This paper argues that in the field of usability, debates about number of users, the use of statistics, etc. in the abstract are pointless and even counter-productive. We propose that the answers depend on the research questions and business objectives of each project and thus cannot be discussed in absolute terms. Sometimes usability testing is done with an implicit or explicit hypothesis in mind. At other times the purpose of testing is to guide iterative design. These two approaches call for different study designs and treatment of data. We apply control systems theory to the topic of usability to highlight and frame the value of iterative usability testing in the design lifecycle. Within this new metaphor, iterative testing is a form of feedback which is most effective and resource-efficient if done as often as practically possible with project resources and timelines in mind.
Practitioner’s Take Away
- Do not debate the appropriateness of specific user research methods in the abstract.
- Before selecting a research method, always clarify the research questions and business objectives of each project and get team buy in.
- Consider iterative usability testing a form of feedback on the progress towards specific design and business goals.
- Start doing iterative testing as early as possible in the design lifecycle.
- Conduct iterative testing as often as practically possible with project resources and timelines in mind.