Evaluation Techniques

Evaluation

Evaluation should occur throughout the design life cycle, with the results feeding back into medications of the design. A distinction is made between evaluation by the designer or a usability expert and evaluation that studies actual use of the system
So :
•tests usability and functionality of system
•occurs in laboratory, field and/or in collaboration with users
•evaluates both design and implementation
•should be considered at all stages inthe design life cycle

Evaluation has 3 main goals:
•Assess extent of system functionality
•Assess effect of interface on user
•Identify specific problems


Cognitive Walkthrough
For each task walk through considers
•what impact will interaction have on user?
•what learning problems may occur?
Analysis focuses on goals and knowledge:
–Does the design lead the user to generate the correct goals?

Cognitive Walkthrough is a detailed review of a sequence of actions, in this case, the steps that an interface will require the user to perform in order to accomplish some known task. The evaluators go through each step and provide a story about why that step is not good for new users. To do so, you need four things: a prototype of the system, a description of the task the user is to perform on the system, a complete written list of the actions needed to complete the task with the system and an indication of who the users are and what kind of experience and knowledge the evaluators can assume about them.