I been reading a book called Adventures in Experience Design written by Carolyn Chandler and Anna Van Slee, and I found a method that seems to be very useful to test how effective an user interface is.
The exercise is just about taking your design with a collection of words that convey positive, negative or neutral feelings and share it with others, so they can choose which words spring to their minds when looking at the design.
Design is all about communication.It is the user communicating with the system model, a conversation between them, and the UI is the channel. Providing a good channel is crucial to succeed with your application. So I went deeper into the technique explained in the book and created a recipe to measure the actual message you are trying to convey with a design.