How to Prevent Human Errors that Poka Yoke doesn’t affect
This article is about how to prevent Human Errors that Poka Yoke doesn’t affect. People’s actions always go through ‘Perception’, ‘Judgement’ and ‘Action’. This post explains major causes and solution ideas in each stage.
(Duration: 8:06)
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Human Errors that Poka Yoke doesn’t affect
Hi this is Mike Negami, Lean Sigma Black Belt.
I received another video request.
“Please make a video about human error prevention in production?”
Thank you, Sekhar for your request. He gave me this request after watching the Poka Yoke video I made earlier.
We would like to make a workplace with Poka Yoke where human errors can’t occur by following the video instructions. However, we cannot set up Poka Yoke for all operations, especially in service operations.
Human Behavior Theory (Carrot and Stick)
Human errors are literally errors that a human made. The first problem here is that it tends to end with someone saying, “It’s a human error. There is nothing we can do.” If this is the case, people stop thinking. There is no action after that.
Please look at this table above. Even if people performed well, for example following the rules, if they were not recognized by their boss or the company, they may eventually stop the good behavior. Also, if they did something bad, for example breaking the rules, and their boss didn’t warn them, they will continue that bad behavior. Unfortunately, this is the reality.
On the contrary, if you recognize their good behavior, they’ll continue it. Also, you can stop their bad behavior by warning them. In any case, it’s important for the company to carefully observe employees’ actions and recognize their actions. Therefore, management is responsible for employees’ behavior.
The solution is using the Carrot and Stick. The timing to give them is also important. The sooner, the better. This is a part of the PDCA Cycle and will improve employees’ motivation.
Cause of Error in each Stage of Action
Next, let’s consider the causes of errors in stages of people’s action which are ‘Perception’, ‘Judgement’ and ‘Action’. The causes of errors are hidden within any of these three stages. Another aspect is that solutions also depend on the conditions of employees, such as ‘Lack of Skills’ ‘Negligent’ and ‘Delinquent’. ‘Lack of Skills’ and ‘Negligent’ tend to apply to beginner and unskilled people. ‘Delinquent’ is more of an experienced person’s error.
First of all, we’ll start with ‘Perception’. An ‘Oversight’, ‘Mis-observation’ or ‘Mis-hearing’ may cause an error. (See the image above.)
Next comes ‘Judgement’ according to the circumstances perceived. Because of ‘Not understanding’, ‘Can’t judge well’ or ‘Mis-judge the situation’, or ‘Assume from custom’, they’ll cause errors.
The last stage is ‘Action’. Although they can act without problems, ‘Forgetting something’, ‘Making a mistake’ or ‘Inadequate behavior and quality’ can cause error. Also, if they become an experienced worker, they may delinquently do ‘Corner-cutting’, take ‘Process shortcuts’ or ‘Violate rules’, then they’ll cause errors. For this, the earlier-mentioned Carrot and Stick are indispensable. You should consider applying a bonus or fine system for this.
How to prevent Human Errors
We’ve learned the background of Human Errors. Now, what action should we take? First, identify where your company’s recent human errors are found within that table. You should count all the errors by section in the table. The one with the highest number is Vital Few, so prioritize thinking about their solutions. If the error causes are the same, you can usually use the same solution.
We’re identifying why they occurred, but at the same time, consider why they were not prevented and how you can prevent it from reoccurring from now on. Let’s consider countermeasures for each cause of error in the table.
Countermeasures in the ‘Perception’ Stage
For the first stage, ‘Perception’, please check and make sure each workplace is where workers can easily perceive any important information. You may be able to make notices easier to read, or use symbols, shapes, or colors to help workers perceive them more easily. Also, you may be able to change from audio communication to visual communication.
Double-display, for example like this, you can show product codes twice side-by-side so that workers can use the 2nd one for verification and you can decrease assumption mistakes. Repetition is when you take orders on the phone, repeat the customer’s order items and quantity so that if there is a mistake, the customer will correct you.
Countermeasures in the ‘Judgement’ Stage
What shall we do in the next stage, ‘Judgement’? Gather experienced workers and ask them for easy and accurate methods, then establish the best practices and standardize those in the company. If there are useful tools, include them in the standard so that everyone can use them. Make SOP or manuals and train them to ensure everyone practices the standard.
Changing settings and processes is common in daily work. Making wrong decisions often occurs when one is not aware of those changes. Clarify the information route and give all workers the necessary information. Clarify accountability for that. In the manufacturing industry, posters and production boards are set up on the wall and used effectively to communicate information.
Countermeasures in the ‘Action’ Stage
The last stage is ‘Action’. Today’s agenda is method for coping when Poka Yoke does not affect, but I would like to point out that you want to set up “a workplace with Poka Yoke where mistakes can’t happen” or “the workers will be alerted when a mistake is about happen” as much as you can.
Another way is to make a To-Do List and have workers work with it. Also, since the workplace environment greatly affects the work performance, please provide a neat, organized workplace to all workers, without Muri, Mura, or Muda, which are Overburden, Unevenness and Waste. Lastly, ‘Sharing Near Misses’.
‘Near Misses’ are one step before the actual incident. The more aware of near misses your workers are, the more they can prevent actual incidents. In my company, we require Unit managers to submit this near-miss report monthly and that is producing good results.
Causes and solutions for human error are various, so I can’t cover everything today, but the most important thing is to not ignore them and to nurture company climate where all managers and employees try to eliminate errors. Indifference is the worst thing.
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