Abstract
Usability evaluation play a key role in the user interfaces development process. It is a crucial part that constrains the success of an interactive application. Usability evaluation is usually conducted by end users or experts after the generation of the user interfaces. Therefore, the ability to go back and makes major changes to the design is greatly reduced. Recently, user interfaces engineering is moving towards Model Driven Development (MDD) process. The conceptual models have become a primary artifact in the development process. Therefore, evaluating the usability from the conceptual models would be a significant advantage with regard to saving time and resources. The present paper proposes a model-based usability evaluation method which allows designers to focus on the usability engineering from the conceptual models. The evaluation can be automated taking as input the conceptual model that represent the system abstractly.