In order to deliver a clean, fresh, and more importantly effective user interface, usability tests are required.
The four principles
Behind every usability test there are different goals, which pertain specifically to the observation aims of the tester. The results can be treated as a control measurement or a baseline. Because several tests can be conducted throughout a period of time, all the results will be compared with the baseline test results.
The four principles behind usability testing are:
Efficiency – the tester measures how much time and how many steps are required for the user to complete basic tasks (find a product, add it to the cart, read the feedback and ratings, ask questions, buy the product. These would be basic tasks for a mobile app such as Amazon.Accuracy – how many mistakes do users make when trying to perform these tasks and how fatal are the mistakes? Sometimes, with the right information, the mistake is recoverable. Recall – after a period of non-use, how much does a person remember about the interface and the browsing process?Emotional response – how does the user feel about the tasks he had to complete? Was the person stressed or confident, and would the user recommend the product to a friend?
Via Marc Phippen