Stepping through your UI and asking two deceptively simple questions at each stage can give you great insights into the problems your users will face.
It's always worth getting real user feedback on your designs. Maximize the value of that feedback by making sure you've removed all the problems you think users will face before you put the product in front of them.
Rick Spencer developed the Streamlined Cognitive Walkthrough Method (PDF link to academic paper) to help impatient developers at Microsoft step through a user interface and find the big issues before they became issues. Rick's pragmatic method works well with time-strapped teams.
Fancy name, simple process
There are just two questions to ask in a cognitive walkthough, and you repeat them for every step of a user's task. "Will the user know what to do at this step," and "If they do the right thing, will they know they did it?".
What's important is keeping the team focused during the session.
- Set the rules up front:
- No designing
- No defending a design
- No debating cognitive theory
- One individual is the leader of the session, to keep people on track.
- Keep the focus on users and their tasks by describing the persona and the scenario that they are trying to accomplish.
- Now the team steps through the interface. At each stage, ask:
- Will the user know what to do at this step?
- If the user does the right thing, will they know that they did the right thing, and that they are making progress towards their goal?
- Note potential stumbling blocks:
- Not edge cases or “maybes” – this is about “best case” scenarios
- Steps where the user might not know what to do or whether they were successful
- Gaps in the design where users aren't led to the next point
- Design ideas, but keep them for a separate discussion
Cognitive Walkthroughs and Heuristic Evaluations
Compare and contrast this method with heuristic evaluations. Both are inspection methods (they don't rely on having users available). Heuristic evaluation applies a set of rules to the interface itself, whereas cognitive walkthroughs attempt to find problems that the user would have when they try to complete their task.
The two techniques complement each other well. A cognitive walkthrough session can sometimes turn into a heuristic evaluation if you don't apply the "no debating cognitive theory" rule. Decide up front whether you care more about interface consistency/correctness or task completion, and then choose heuristic evaluations or cognitive walkthroughs respectively.