Assigning probability values to errors is still very much an art form. Nonetheless, there is sufficient general agreement about the likelihood of errors occurring in various generic tasks to put them into sensible rank order. Their main use is to provide benchmarks for the range of error probabilities over different jobs.
Here is a list of several well-researched error-enforcing conditions (EEC). For each one, there are the following:
- Description: a general description
- Risk factor: a number (x10) representing the approximate amount by which the nominal error probability will increase when someone encounters this EEC initially (the error probability cannot exceed 1.00)
- Error type: the most likely types where these can be predicted on psychological grounds. The conditions are listed in order of severity, beginning with the most provocative conditions.