A product is never perceived the same way by its designer and its user. Both are nevertheless doing their best to create and use it.

Differences in goals and identified priorities between users and designers might lead to difficulties for users and sometimes might get users to dismiss product.

User tests are a mandatory and important step to identify user needs in front of the proposed new product.

Tests allows us to identify difficulties thanks to scenarios built on future uses of the product.

By bringing prototypes to users, we allow users to give us valid feedbacks on how they shall play, use or modify previous mean of the product; thus allowing us to anticipate theses new needs and to integrate them in the delivered product.