Product Designer interview question
How do you make an interaction-design decision?
Choose an interaction by the user's goal, context and mental model, make system state and next actions visible, minimize error cost, compare alternatives with prototypes, test representative tasks, and include keyboard and assistive use.
Direct answer
What a strong answer covers
How it works
An interaction decision starts from what the user is trying to do, in what context, and what they already expect from similar tools, because a pattern that matches their mental model needs no explanation. The design makes the system’s state visible, shows what actions are available and what will happen, and keeps the cost of a mistake low through confirmation for destructive actions, undo where possible, and clear recovery. Alternatives are compared with prototypes rather than argued, tested on representative tasks with real users, and the choice covers keyboard, screen reader, and touch from the start rather than as a retrofit.
Example
Deciding how users delete items in bulk, the team prototyped a checkbox-and-toolbar pattern and a swipe-to-delete pattern. Testing with eight users on a task of removing five items showed the toolbar pattern faster and less error-prone on desktop, while swipe suited single items on mobile. The shipped design used the toolbar with an undo toast instead of a confirmation dialog, and keyboard selection with shift-click was verified in the same tests.
Common mistakes
- Choosing an interaction because it looks novel rather than because users expect it.
- Hiding system state so users cannot tell whether an action took effect.
- Designing for mouse first and bolting on keyboard and screen-reader support later.
A useful answer structure
Answer from your own work.
Do not memorise a script: use only examples you can explain honestly in follow-up questions.
Open the desktop workspace and rehearse a clear answer in your own words.