Discount Usability: 20 Years

Simple user testing with 5 participants, paper prototyping, and heuristic evaluation offer a cheap, fast, and early focus on usability, as well as many rounds of iterative design.

Nielsen, Jakob. Alertbox (2009). Articles>Usability>Testing>Methods

Moderating with Multiple Personalities: Three Roles for Facilitating Usability Tests

Usability tests are a core design tool and, when done well, they deliver tremendous insights to the team. However, when a usability test is done poorly, it can be a disaster for everyone involved. An important key to their success is the work of a great moderator.

Spool, Jared M. User Interface Engineering (2009). Articles>Usability>Testing>Methods

Usability Over Time: Longitudinal Research Studies

User research focused on single experiences with a feature or workflow uncovers different problems and issues than longitudinal research.

Sy, Desirée. Designing the User Experience at Autodesk (2009). Articles>Usability>Testing>Methods