Usability is an approach to product development that incorporates direct user feedback throughout the development cycle in order to reduce costs and create products and tools that meet user needs.
Two international standards define usability and human-centered (or user-centered) design:
"[Usability refers to] the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use." - ISO 9241-11
"Human-centered design is characterised by: the active involvement of users and a clear understanding of user and task requirements; an appropriate allocation of function between users and technology; the iteration of design solutions; multi-disciplinary design." - ISO 13407
The business benefits of adding usability to a product development process include:
• Increased productivity
• Increased sales and revenues
• Decreased training and support costs
• Reduced development time and costs
• Reduced maintenance costs
• Increased customer satisfaction
