High-Cost Usability Sometimes Makes Sense

Computing the net present value (NPV) lets you estimate the most profitable level of usability investment. For big projects, expensive usability can pay off.

Nielsen, Jakob. Alertbox (2007). Articles>Usability>Project Management>Planning

Usability Requirements: Making User Satisfaction a Measure of Product Success  

Defining usability requirements at the beginning of the project increases the chances that the end product will meet the users' goals and create a satisfying user experience. Unfortunately, such requirements are often not considered with the same priority as functional or other technical requirements. This presentation defines usability requirements, proposes guidelines for creating measurable requirements, and elaborates the components of a well-constructed usability requirement.

Bachmann, Karen L. STC Proceedings (2004). Articles>Project Management>Planning>Usability