April 21, 2013
Usability testing involves typical users using the system (or product) in a realistic environment.
There are two main types of usability testing: formative evaluation and summative evaluation.
Formative evaluation is conducted early in the design process to find and fix problems as part of an iterative design process to make an interface more usable. It provides valuable insights of where users have difficulty reaching their user goals with the technology or service. For formative evaluation, the facilitator will normally be with the user to prompt and question when necessary.
Thinking-aloud method and retrospective method are some methods that can be used for formative evaluation.
Summative evaluation is used to obtain measures to establish a usability benchmark or to compare results with usability requirements. The main purpose of a summative test is to evaluate a product through defined measures, rather than diagnosis and correction of specific design problems. It generally involves a larger number of participants. Summative evaluation normally do not have a moderator in the room with the participant, and the focus is much more on timing the tasks and specifically tracking everything the participant does to tackle a particular task.
Performance measurment can be used for formative evaluation.
Location for usability testing
Usability tests are typically held in a specially designed room called a usability lab (usability laboratory).
A fixed usability laboratory with multiple cameras and one-way mirrors can stick observers in a separate observation room and leave the user and facilitator alone to concentrate on the test tasks.
However, You can do effective usability testing anywhere such as a conference room, the user's home, work space, or even remotely with the user in a different location.