Interaction Design is the process of designing how users interactive with the functionality of a particular product. This involves selecting interface components and arranging them in a way that supports the tasks the user is trying to accomplish.

Based on initial task analysis which identifies they way users work, a conceptual model for interaction can be designed that supports the user's perceptions and needs. This conceptual model will be documented through a series of interaction workflow diagrams and supporting wireframe schematics that define the skeleton of the final interface.

It is important during this phase, that time is taken to conduct user evaluations designed to test the assumptions and solutions of the interaction conceptual model. These evaluations are part of an iterative design process used to refine the final interaction design for the product.

Creating the interaction design involves:

• Review and organize site objectives. User experience designers should always be reminded of the "why" involved in any project as defined in the site objectives and strategy. This information allows the comparison of these objectives against the user's perception.
• Review task analysis and functional specification. Use case scenarios are an essential tool to defining the interaction design for a product. These scenarios will provide the insight to the user's mental process that will be essential in defining the conceptual model used to arrange the interface components of the application.
• Create interaction workflow diagrams. These interaction workflows specify every user interaction with the underlying functional system and the resulting process. These diagrams also identifying all system contingencies and associated error conditions that may sabotage certain tasks. These workflows will also be added to the functional specification as supporting documents for the development of the back-end systems.
• Create wireframe schematics and interface specifications. Once the interaction workflows are understood, a series of schematic mockups can be created that located interface components on individual page representations. Each page will be annotated with written specifications describing in detail the behaviors of the individual components and overall interaction. These wireframes serve as the outline for the final visual treatment for the final interface.