Design · User Experience Design
A topic within User Experience Design, itself one of 11 topics in that field and part of Design.
2 works
John Brooke
Introduces a ten-item questionnaire for scoring an interface's perceived usability, arguing that a short, cheap, technology-independent scale gives more reliably comparable results than ad hoc surveys.
Jakob Nielsen & Thomas K. Landauer
Derives from pooled study data that usability problems are found with steeply diminishing returns after a handful of test participants, giving the mathematics behind the later 'five users' heuristic.