User Control and Freedom
Let people go back, cancel, or undo without losing their work.
People explore more freely when they know they can get back.
You open a full-screen panel, tap Back, and land two pages away. The control existed, but it did not do what you expected. User control means every exit takes people where it says it will, without losing their work.
Origin
Nielsen made this the third heuristic in his 1994 revision. People need visible ways to leave a flow, go back a step, and undo changes. Maria Rosala expanded the guidance for NN/g in 2020.
Keep Back predictable. It should return people to the previous state, not restart a flow or move them somewhere else.
Provide a clear Cancel option for long or multi-step tasks. Do not make people click Back several times just to leave.
Support Undo for changes people may make by mistake. If several actions can happen quickly, provide multiple Undo and Redo steps.
Make recovery visible. Do not rely only on a gesture or keyboard shortcut that people may never discover.
Digital systems
Google Drive's undo snackbar
When someone renames a file in Google Drive, a snackbar confirms the change and offers Undo. It appears immediately, so recovery does not require opening a menu.
Physical signals
Emergency exit signs
Emergency exits are marked so people can find them quickly. Digital exits need the same clarity. Back, Close, and Cancel should be visible before someone needs them.
When exits are hidden or behave unexpectedly, people can lose work or feel trapped in a flow. They become less willing to explore because every choice carries more risk.
Make Back, Close, Cancel, Undo, and Redo easy to find and predictable. Preserve work whenever possible, and explain clearly when leaving will discard it.