Editing Usability (section)

===Empirical measurement===
Test the system early on, and test the system on real users using behavioral measurements. This includes testing the system for both learnability and usability. (See [[#Evaluation methods|Evaluation Methods]]). It is important in this stage to use quantitative usability specifications such as time and errors to complete tasks and number of users to test, as well as examine performance and attitudes of the users testing the system.<ref name="pages.cpsc.ucalgary.ca"/> Finally, "reviewing or demonstrating" a system before the user tests it can result in misleading results. The emphasis of empirical measurement is on measurement, both informal and formal, which can be carried out through a variety of [[#Evaluation methods|evaluation methods]].<ref name="Gould, J.D. 1985"/>