We deleted our "Are you sure?" dialog. Mistakes went down.

We had confirmation dialogs on 14 destructive actions. We assumed they were preventing errors.

We measured across 500,000 sessions:
Errors prevented by confirmation: unmeasurable
Users who clicked through confirmation without reading: 94%
Median time on confirmation dialog: 0.6 seconds
Users who reported an accidental action despite confirmation: 3.1% of all actions

The dialog was not a safety net. It was a speed bump people had learned to ignore. 94% of users were clicking "Yes" before their eyes had focused on the text. The confirmation was training people to confirm without thinking.

We replaced the dialogs with undo. Every destructive action became reversible for 10 seconds with a visible undo bar.

Accidental actions reported dropped from 3.1% to 0.9%, and users performed destructive actions 22% more often because they trusted the safety net.

What confirmation dialog are your users clicking through without reading, and would undo work better?