Usability Testing 101
Why do we need to do usability testing? Won’t a good professional UX designer know how to design a great user interface?
Even the best UX designers can’t design a perfect — or even good enough — user experience without iterative design driven by observations of real users and of their interactions with the design.
There are many variables in designing a modern user interface and there are even more variables in the human brain. The total number of combinations is huge. The only way to get UX design right is to test it.
This article is a nice basic summary of why and how to conduct successful usability testing.