Usability measures characteristics such as consistency and aesthetics in the user interface. Consistency is the constant use of mechanisms employed in the user interface while aesthetics refers to the artistic, visual quality of the user interface.

It is the ease at which the users operate the system and make productive use of it. Usability is discussed with relation to the system interfaces, but it can just as well be applied to any tool, device, or rich system.

This addresses the factors that establish the ability of the software to be understood, used, and learned by its intended users.

The application interfaces must be designed with end users in mind so that they are intuitive to use, are localized, provide access for differently abled users, and provide an excellent overall user experience.

The following attributes are:

• Look and feel standards: Layout and flow, screen element density, keyboard shortcuts, UI metaphors, and colours
• Localization/Internationalization requirements: Keyboards, paper sizes, languages, spellings, and so on