the 16 human error modes
When designing a process or product which involves interaction with humans you need to take into account that there will be a potential risk a human error will occur. These risks have to be mitigated in order to create a good process or product. The best way is of course to eliminate the possibility that a human error can occur, but if this is not possible you should try to detect it as early as possible so that it can be corrected.
The sixteen human error modes help you to identify where there is a potential risk for human errors. By going step by step over your process or product features and checking it against each of the 16 modes you can identify the weak points and brainstorm a solution.
Let's go over the 16 human error mode taking a daily task which is prone to human errors, like driving a car as an example:
1. Omission
A part of the process is being omitted.
When starting a car you can be distracted by many thoughts: which route to take, which groceries to pick up, ... putting your seatbelt on is therefore often omitted. Therefore modern cars have a warning light with an associated audio signal to warn you if you or one of your passengers forget to put the seat belt on.
2. Excessive/insufficient repetition
A part of the process is being excessively repeated or insufficient repeated.
Your car manual describes how many times you have to check your tire pressure. Unfortunately, many people do not check their tyre pressure regularly which results in higher fuel consumption. Therefore modern cars use a warning signal to indicate that the tyre pressure is too low and should be checked. this is a mean to protect the process against insufficient repetition.
3. Wrong order of sequence
Two or more proces steps are executed in the wrong order of sequence.
when switching lanes you have first to look if the lane you want to move too is free before you put on your blinkers. Drivers frequently with this sequence around, putting on the blinkers so that cars in the other lane hopefully break or accelerate so that the driver can start his maneuver. A lot of focus is placed on this in driving school.
4. Early / Late Execution
A part of the proces is done to early or to late.
When driving a car, you need fuel. When you are running out of fuel (late execution of refuelling) a warning light will come up.
5. Execution of restricted work
A part of the process is done by unauthorized personnel.
When your car needs maintenance you could do a lot by yourself if you are a handy person and have the necessary knowledge, but if not the change is high that a mistake could occur. Therefore car manufacturers only give you a warranty if you go with your car to an authorized garage for maintenance.
6. Incorrect selection or identification
An object is incorrectly selected or identified.
At the fuel pump, you have to choose your type of fuel: petrol, diesel, ... A mistake can happen that you select the wrong type of fuel for your car. For example, if you are driving a rental car with another type of fuel than your regular car or if you just have bought a new car. Therefore gas stations work with different color codings and depending on the type different diameters are used for the fuel nozzles and fuel inlets.
7. Incorrect counting or calculating
An object / characteristic is incorrectly counted, measured or calculated.
Luckily you do not have to count or calculate many things when driving a car so that you can focus on the road. There are however examples where you have to do some offline measurements. Measuring how much oil you still have is one of these activities. In order to make sure that you have the right quantity a dipstick is used with an indication of the maximum and minimum level.
8. Misrecognition / Misunderstanding / Misreading
An incorrect decision is made due to the misrecognition of the state of the object or misunderstanding available information. The state of the object/information is overlooked or miscommunicated.
Paying attention to the traffic and surroundings while meanwhile look for your directions can be challenging. There are not many drivers who never have missed a turn. A GPS can assist in finding the right way.
9. Failing to sense danger
A danger situation which is prone to be overlooked.
Sitting in a car can give a sense of false safety. A nice example is during the winter when ice can be formed on the road while sitting in a heated car. The road can become slippery without noticing. Therefore some cars are equipped with a frost warning light on the dashboard which helps to keep drivers safe and more aware of their surroundings. This warning light is fed by a temperature sensor which is located around the front bumper, away from the heat of the engine.
10. Incorrect holding
An object is hold incorrectly which will have a impact on the motion to be done.
Having two hands on the steer is crucial in order to quickly react when needed. There are different techniques that are taught. For example, the “9 and 3” which means that you place your left hand on the left portion of the steering wheel in a location approximate to where the nine would be if the wheel was a clock and the right hand should be placed on the right portion of the wheel where the three would be located. During your driving course, you will learn the right technique for your car.
11. Incorrect positioning
An object is placed in the wrong position.
Luckily you are not always sitting in your car. This mean that you have to park (position) your car in a valid parking spot. If not your risk a fine. Road markings and signs help you to place your car in a valid spot.
12. Incorrect orientation
A object is placed/moved in the wrong orientation.
When standing on a parking lot (correct position) and you are not respecting the direction in which you should park (incorrect orientation). Parking lines can help.
13. Incorrect motion
A motion or movement that is not correct.
Although most people use GPS now, it could be that when you are planning a route yourself that you are not selecting the optimal route leading to extra fuel consumption and/or time.
14. Improper holding
Improper holding of an object while executing the movement.
15. Inaccurate Motion
When executing the movement, the motion deviates from what is planned.
Every car driver has experienced it, a quick moment where your attention slips and you are driving over the line: an inaccurate motion has taken place. New cars are equipped with line recognition sensors in order to warn you when moving to short to a line (without using your direction indicator lights).
16. Insufficient Avoidance
An object that can be unintentionally touched, stuck or splashed.
Car collisions happen unfortunately way too much. Often it is due to not keeping enough distance to the car in front of you. In order to reduce the risk, new cars can be equipped with distance sensors who warn you if you are driving to close to the car in front of you and even brake automatically when the car in from of you is slowing down.
Summary
The sixteen human error modes help you to identify where there is a potential risk for human errors. Go over your process step by step, in each step go over the 16 human error modes and see if they can occur. Modes 1 to 5 are potential human errors if the work progress is not understood. Mode 6 and 7 are related to what could go wrong when selecting the work object. In mode 8 it is checked if the work objects can be recognized properly. Mode 10 to 13 focus on the recognition of the motion that has to be done with the work object. While mode 9 checks if the danger related to the motion can be recognized sufficiently. At last mode 14 to 16 describe which potential human errors could occur during the execution of the motion.
