The Nature of Human Error

Taken from The Human Contribution: Unsafe Acts, Accidents and Heroic Recoveries

Reason says that error is generally considered to be some form of deviation. These can be:
* From the upright (trip of stumble);
* From current intention (slip or lapse);
* From an appropriate route towards some goal (mistake);
* Straying the path of righteousness (sin)

A variety of classifications and taxonomies have been developed over the years the explain error, which fall into four basic categories:

1. Intention - Was there an intention before action, was intention the right one and were the action performed correct to achieve the intention?

2. Action - Were there omissions, unwanted or unintended actions, repetitions, actions on the wrong object, misorderings, mistimings or merging of actions?

3. Context - Deviating because you are anticipating what is coming or echoing the past, have been primed to follow a pattern that does not work for all circumstances, you are disrupted, or distracted or stressed.

4. Outcome - Looking at errors according to the outcome, which can include inconsequential free lessons, exceedances working near the edge of safe limits, incidents and accidents.

There are many myths about errors. Reason suggests the following:

1. Errors are intrinsically bad - trial-and-error learning is essential if we are to understand novel situations.

2. Bad people make bad errors - in fact it is often the best people that make the worst errors because they may be in positions of responsibility and tend to push the limits by trying out new techniques

3. Errors are random and variable - we can actually predict the type of error likely to occur based on situation.