User Interaction Functional Specification (UIFS)

The UIFS is a design document. It defines all user scenarios and some prototyping techniques that test the role of each element, its look and feel, and its implementation, in a draft form. The users should be able to comment on it and Engineering should be able to use it in development. The UIFS is where the user's mental model, the interaction designer's model, and the engineering model are first compared.

What's in the UIFS is a full definition of specific tasks the product will contain, oriented to the user personas and mental model defined earlier. It will include use cases, wireframes, and prototypes for iterative usability testing. This is where the first draft of the information architecture will be stated, beginning with the outer taxonomy. This information architecture corresponds to the user's mental concept of the product.

The user interaction designer should write the UIFS, with the sole concern of meshing the user experience with the various stakeholder, customer, and technical requirements of the project.

Information Architecture

Applications, or Websites that are primarily about reaching goals, have fewer pages than information-heavy sites, so site maps may represent workflow instead of structure. Navigation and labeling are still important, and there is more emphasis on scenarios and wireframes to represent the design.

User Interface Design

Visual design can begin early, as it will include corporate and product branding that may already exist, such as in a product family, along with Marketing direction as to look and feel. The creation of graphic design elements and visual motifs for the user interface can develop in parallel, and be included in wireframes and prototypes. Prototype testing will provide feedback to the interface designer.

Implementation

As code for each scenario is completed, the interaction designer and the team must review those with the current functional spec to ensure the team is building what all stakeholders agreed on. Usability observations can begin during implementation.

Interaction ideas and modifications will come up during all development phases, including implementation. The interaction designer will incorporate these changes to wireframes and prototypes so that the functional specification always reflects what is being built.

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