Information architecture (IA) focuses on the organization of data—that is, how data is structured from a user’s perspective, as opposed to the system, or technical, perspective. At the level of the page layout, information architecture ensures that data is logically grouped and interrelated.
Concerns the controls, mechanisms, and processes that users require to perform their tasks on systems and so meet their goals. interaction designer determines whether to use a menu rather than a set of tabs, whether to use a drop-down list rather than set of radio buttons, and the process, or steps, for setting up a new email account using a wizard.
Focuses on the aesthetics of a user interface, ensuring that it looks good, communicates the right image to users, and conforms to any brand guidelines. corporate identity, illustration, animation, icon, or photography is integrated into the interface design work.
Is primarily about planning and executing various types of usability studies that test how well people can use a user interface, then making recommendations for how to correct the problems that these studies identify.