Designers usually make many assumptions about users’ familiarity with the technology, and the way they might use the product in the real world.

According to a Survey by

” 92% of respondents checked social media on the phone in the past month, 31% stayed in the bathroom longer than necessary to finish activity on their phone “

But do we take account of these scenarios during the design of our digital products? Not likely right ? Which means that some design decisions turn out to be wrong when the product gets into the hands of actual users which arises due to some unanticipated user behaviors.

All conceivable human behavior cannot be catered for and there will be some just too bizarre to ever anticipate and fix. But there are certain types of error that can be predicted and, to some extent, designed for, to ensure the user experience isn’t compromised too much by their occurrence.

Errors happen and unintended actions are inevitable.

They are a common occurrence in usability tests and are the result of problems in an product design / interface and imperfect human actions and It is valuable to have some idea about what these are, how frequently they occur, and how severe their impact is.

Don Norman has written extensively about slips and mistakes in The Design of Everyday Things and can be categorized into 2 broad causes of human errors.


Slips are the classic unintended action a user makes while trying to do something on an interface even though the goal is correct (e.g., a typo).


Mistakes are made when users have goals that are inappropriate for the current problem or task; even if they take the right steps to complete their goals, the steps will result in an error.

classic slip example in ux design