Errors come in kinds
Norman (1983) and Reason (1990) separate slips, where execution goes wrong, from mistakes, where the intention itself is wrong. Tapping the wrong button is a slip; misunderstanding which address a field wants is a mistake. Per Rasmussen (1983), slips dominate automatic actions and mistakes unfamiliar ones. Prevent slips with structure and mistakes with clear explanation.
Constraints and defaults
Shingo's (1986) poka-yoke makes errors impossible, like parts that only fit one way. On screens: date pickers, disabled past dates and numeric keypads. Sensible defaults reduce input. Separate and restyle dangerous buttons (Laubheimer, 2015). This ties to mobile form usability.
Confirmation and undo
Sellen (1994) shows people catch errors by seeing outcomes, so immediate results plus undo are the strongest safety net. Confirming everything with dialogs trains habitual 'OK'. Reserve confirmation for irreversible payments or deletions and say exactly what will be lost. WCAG 2.2 (W3C, 2023) 3.3.4 requires reversal, checking or confirmation for financial and legal submissions.
FAQ
- How does prevention differ from error messages?
- Prevention stops errors; messages help fix them. Prevention comes first.
- When to use confirmation dialogs?
- Only for irreversible, high-impact actions; overuse makes users click through.
Sources reviewed: 2026-10-27
References
- Norman, D. A. (1983). Design rules based on analyses of human error. Communications of the ACM, 26(4), 254–258. Derives design rules from types of human error.
- Reason, J. (1990). Human error. Cambridge University Press. Classic taxonomy of slips, lapses and mistakes.
- Rasmussen, J. (1983). Skills, rules, and knowledge; signals, signs, and symbols, and other distinctions in human performance models. IEEE Transactions on Systems, Man, and Cybernetics, SMC-13(3), 257–266. Skill-, rule- and knowledge-based performance model.
- Sellen, A. J. (1994). Detection of everyday errors. Applied Psychology, 43(4), 475–498. How people detect their own errors.
- Laubheimer, P. (2015, August 23). Preventing user errors: Avoiding unconscious slips. Nielsen Norman Group. Practical UI guidance against slips.
- Shingo, S. (1986). Zero quality control: Source inspection and the poka-yoke system. Productivity Press. Introduced poka-yoke mistake-proofing.
- World Wide Web Consortium. (2023). Web Content Accessibility Guidelines (WCAG) 2.2. Criterion 3.3.4 requires reversible, checked or confirmed submissions.