One of Jakob Nielsen’s 10 Usability Heuristics concerns user error prevention, and it is perhaps among the most important ones. Having a good design process in place, an understanding of the concept of mental models, and conducting usability tests can uncover potential areas of user error. These can then be addressed through design improvements targeting error prevention.
Two Categories of Errors
In The Design of Everyday Things, Don Norman categorizes errors into slips and mistakes. Slips take place at a subconscious level and occur when an action is not done correctly; you intend to do one thing and end up doing something else. Slips also occur during the execution of a plan or in the perception or interpretation of the outcome. Mistakes are conscious deliberations, they “occur when the wrong goal is established or wrong plan is formed”.
Norman further breaks down slips and mistakes into classes. Let’s look at each of these further. Continue reading