Chapter 5. The Craft of Interaction Design

After defining the project, interviewing stakeholders, and conducting design research, interaction designers next make a series of models, diagrams, and documents. Indeed, this is how designers design. Many of these items are paper documents, but they can be physical or digital representations as well. Designers use these models and diagrams to demonstrate their skill, knowledge, and ideas as well as to visualize and analyze what they learned earlier in the design process.

There is a perennial debate about design documentation: how much do you need? Some designers suggest jumping straight into prototyping, saying that far too many documents are created. Others wouldn't dare proceed without most of these documents for fear that something important wasn't written down somewhere.

My answer is that designers need exactly as much documentation as it takes to execute the project well. If the designer's team responds well to use cases, then by all means the designer should produce them. If a client couldn't care less about a task analysis, the designer shouldn't perform one unless the designer personally finds it helpful.

The only reason for interaction designers to make the models and diagrams they do is to communicate their knowledge of and vision for a project. Research models show what was learned from the user research. Personas demonstrate an understanding of the audience. Use cases and task analyses outline what the product or service needs to accomplish. Mood boards, scenarios, storyboards, task flows, sketches, wireframes, and prototypes pull all the pieces together into a vision of what the final product or service will be. Testing makes sure that that vision is shared by the users.

If a document doesn't communicate anything useful, it is worthlessless than worthless, in fact, because it squanders the designer's time. Each model or diagram produced should take the project one step further toward completion. These design documents are at the heart of the craft of interaction design.