Errors can take a wide variety of forms, none of which are necessarily predictable on the basis of the individual’s experience and knowledge level. However, some factors that may have a profound effect are:

• overconfidence;
• incomplete or inaccurate mental models - which may result in the application of and improper technique; and
• motivation - if motivation is too low, for example because the task at hand is considered irrelevant or not interesting, a person will force him/herself to concentrate on what he/she is doing. This will increase the probability of distractions interfering with the task, attention will generally be low and performance will be as well. Tasks tend to be carried with "less care".