Reviewing User Interfaces
http://www.uxmatters.com/mt/archives/2009/02/reviewing-user-interfaces.php

Bracey, Rhonda
UXmatters
2009

Abstract:

While user interface (UI) reviews often occur at the end of the development cycle, I recommend that you get involved early in the process, preferably when the designers create the initial wireframes or paper prototypes. Why? Making changes early in the process reduces development costs. Plus, if you identify usability issues early, it’s much more likely the team can remedy them before launch, preventing bad reviews.