| 1 |
Unfamiliarity with a situation which is potentially important but which only occurs infrequently or which is novel |
×17 |
| 2 |
A shortage of time available for error detection and correction |
×11 |
| 3 |
A low signal-noise ratio |
×10 |
| 4 |
A means of suppressing or over-riding information or features which is too easily accessible |
×9 |
| 5 |
No means of conveying spatial and functional information to operators in a form which they can readily assimilate |
×8 |
| 6 |
A mismatch between an operator’s model of the world and that imagined by a designer |
×8 |
| 7 |
No obvious means of reversing an unintended action |
×8 |
| 8 |
A channel capacity overload, particularly one caused by simultaneous presentation of no redundant information |
×6 |
| 9 |
A need to unlearn a technique and apply one which requires the application of an opposing philosophy |
×6 |
| 10 |
The need to transfer specific knowledge from task to task without loss |
×5.5 |
| 11 |
Ambiguity in the required performance standards |
×5 |
| 12 |
A mismatch between perceived and real risk |
×4 |
| 13 |
Poor, ambiguous or ill-matched system feedback |
×4 |
| 14 |
No clear direct and timely confirmation of an intended action from the portion of the system over which control is to be exerted |
×4 |
| 15 |
Operator inexperience (e.g., a newly-qualified tradesman, but not an "expert") |
×3 |
| 16 |
An impoverished quality of information conveyed by procedures and person/person interaction |
×3 |
| 17 |
Little or no independent checking or testing of output |
×3 |
| 18 |
A conflict between immediate and long-term objectives |
×2.5 |
| 19 |
No diversity of information input for veracity checks |
×2.5 |
| 20 |
A mismatch between the educational achievement level of an individual and the requirements of the task |
×2 |
| 21 |
An incentive to use other more dangerous procedures |
×2 |
| 22 |
Little opportunity to exercise mind and body outside the immediate confines of a job |
×1.8 |
| 23 |
Unreliable instrumentation (enough that it is noticed) |
×1.6 |
| 24 |
A need for absolute judgments which are beyond the capabilities or experience of an operator |
×1.6 |
| 25 |
Unclear allocation of function and responsibility |
×1.6 |
| 26 |
No obvious way to keep track of progress during an activity |
×1.4 |
| 27 |
A danger that finite physical capabilities will be exceeded |
×1.4 |
| 28 |
Little or no intrinsic meaning in a task |
×1.4 |
| 29 |
High-level emotional stress |
×1.3 |
| 30 |
Evidence of ill-health amongst operatives, especially fever |
×1.2 |
| 31 |
Low workforce morale |
×1.2 |
| 32 |
Inconsistency of meaning of displays and procedures |
×1.2 |
| 33 |
A poor or hostile environment (below 75% of health or life-threatening severity) |
×1.15 |
| 34 |
Prolonged inactivity or highly repetitious cycling of low mental workload tasks (for 1st half hour) |
×1.1 |
| 34 |
(Thereafter) |
1.05 |
| 35 |
Disruption of normal work-sleep cycles |
×1.1 |
| 36 |
Task pacing caused by the intervention of others |
×1.06 |
| 37 |
Additional team members over and above those necessary to perform task normally and satisfactorily (per additional man) |
×1.03 |
| 38 |
Age of personnel performing perceptual tasks |
×1.02 |
