Usability Objectives (Revisited)

For this class, we will standardize on the following definitions:

  • Utility (aka usefulness). Is this something people want to do?
  • Learnability. Is this something that people are able to do?
  • Efficiency. Is this something people can do quickly (assuming they are already able to do it)?
  • Effectiveness. Is this something people can do well?
  • Satisfaction. Is this something people enjoy doing?

Note that learnability and efficiency can be directly observed in usability tests.

Effectiveness probably requires a rubric to assess the quality of the result.

Errors may affect learnability, efficiency and effectiveness.

Other dimensions such as accessibility are important but are not emphasized in this class.