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Interesting Topic Human Factors as Root Cause

Bev D

Heretical Statistician
Staff member
Super Moderator
#3
Operator errors are a fact of life. Human beings are nor robots. In my experience bringing forth human error is accepted when the corrective actions are not re-trained the operator or disciplined the operator. If we propose true error proofing and error reduction methods as corrective actions accompanied by a solid cause analysis that points to human error, it will be accepted.
 

TechnicalGuy

Research and Development
#4
I agree, human errors can occur. When we audit we are told not to accept human errors as a root cause because it is a problem with the system put into place that allow that error to occur, e.g. lack of inspection, lack of training, not enough validation on training effectiveness, not enough resources etc. Simply saying human errors can just put a problem to one side instead of identifying a real opportunity to improve the system.
 

JoshuaFroud

Involved In Discussions
#5
any suggestions on how to describe human factors as a root cause for a non-conformity without is sounding like "operator error"
I would look closely at the problem, the root cause of the error may have been a mistake, however, was this detected at the first possible check/inspection point if not I would suggest that as these points also failed your corrective action can look to addressing detection system issues rather than the almost unsolvable "mistake".
 

TPMB4

Quite Involved in Discussions
#6
Doesn't that depend on the inspection / detection method available? If it's only visual inspection then you can't guarantee it will detect every defect. If you can't put in place less human based detection then human error is part of visual inspection.

With visual inspection what corrective actions are possible? Allow more time to inspect, provide better training or boundaries of what is or isn't acceptable, use of simple to use go/no go gauges? At the end of the day there is still those 4 human errors.
 

John Predmore

Involved In Discussions
#7
My company made huge advances in quality (and quality thinking) when they began asking “Five Whys on Three Levels”.

The first level is why did a particular reject or failure or accident occur. This is the traditional Five Whys. But don’t stop there.

The second level was why did the countermeasures, which should have been in place, fail to detect or prevent this particular problem, or allowed the problem to escape or escalate? This second line of inquiry tends to focus engineers and group leaders in the direction of error-proofing and preventive action.

The third level tends to lay the problem at the feet of management, consistent with Deming’s adage that management is ultimately responsible for performance of the system. Why was this problem not foreseen or not recognized or not addressed? What more could factory leadership have done to prevent this type of problem? Maybe there was a change in conditions which was not recognized or reacted to. Or maybe the planned countermeasure was not effectively implemented or not maintained over time. The third line of inquiry encourages us to see how lessons learned could read-across to similar potential areas for improvement.

The consequence of looking at every problem on three levels is this paradigm generates at least 3 opportunities to prevent or mitigate problems.
 

Bev D

Heretical Statistician
Staff member
Super Moderator
#8
Five Whys on three levels is a decent approach. I utilize something similar incorporating the 'swiss cheese' theory of causes for human error. too often we think about 'root cause' as a one dimensional thing when really it is multi-dimensional so I tend to use the term 'causal mechanism' to not constrain thought. the swiss cheese theory for human error includes organizational conditions, workplace conditions, latent conditions and actions. Additionally we think about the 'escape mechanism'. While we may never completely eliminate human error, we can make substantial strides in reducing human error and it's ability to produce defects.

let me provide an example: we had a receiving person put the wrong label on a chemical upon receipt. They actually 'switched' labels between chemical A and Chemical B. Why - well because he could. We investigated further understanding the actual sequence of what happened. The two chemicals were ordered from the same supplier. they had really chemical names that the receiver didn't understand. the names were very similar. in fact, they were exactly the same for the first dozen or so characters. The lot number and part number on the supplier label were different from the lot number the company assigned (We pre-assign lot numbers for this class of chemicals after a pre-shipment qualification test) and the part number that we ordered against (part numbers are different for difference suppliers for this commodity level class of chemicals.) Chemical B came in first. The receiver put the A label on and received the part against the A line item on the PO. Of course when Chemical A came in the only line item available was for chemical B so A got B's label and voila! two bad things. Now the manager of the area wanted to discipline the operator saying that if he was unsure he was supposed to set it aside for someone else to figure it out. I asked the manager to go observe receiving during the same time frame as when the label mixup. he came back after an hour and said "wow. it's a miracle they get any label correct." the speed of receipts is incredible and there is very little room to hold material in the area or on a truck. it 'must' be moved quickly into the assigned storage area to allow for more stuff to offloaded form the trucks and received in and moved. chaos is a goo description. Clearly the organizational factors of 'receive the parts quickly' and the cramped workplace conditions along with the part number. lot number disparity and a very long nonsensical chemical name conspired to result in the action of mislabeling the first chemical. the latent condition of the wrong received line item led to the second chemical being mis-labeled. We had to make a couple of changes: we made it impossible to have a PO for certain types of chemicals that come from the same supplier and have similar names on the same PO. (the purchasing manager was initially opposed to this but the buyer really liked the change - said it made his job a lot easier.) Then we also had our ERP system change to use the same part number as whatever the supplier used and we eliminated the company specific lot number assignment. then the PO and the Label had the same information... It didn't really take that long (the error was quite expensive though) to get to a real solution once we moved people away from blaming others and carping that the operator needed to have better discipline or whining that we would never eliminate all errors. Someone wanted to implement a separate inspection for the labels; it didn't work because all of the conditions that led to the original mistake were still on place. and the error rate was actually very low so that the 'inspectors' rapidly became complacent.

The issue people have about claiming operator error and then offering training or discipline as the corrective action is that it is a very shallow understanding with a very shallow correction action that simply isn't effective...
 
#9
Five Whys on three levels is a decent approach. I utilize something similar incorporating the 'swiss cheese' theory of causes for human error. too often we think about 'root cause' as a one dimensional thing when really it is multi-dimensional so I tend to use the term 'causal mechanism' to not constrain thought. the swiss cheese theory for human error includes organizational conditions, workplace conditions, latent conditions and actions. Additionally we think about the 'escape mechanism'. While we may never completely eliminate human error, we can make substantial strides in reducing human error and it's ability to produce defects.

let me provide an example: we had a receiving person put the wrong label on a chemical upon receipt. They actually 'switched' labels between chemical A and Chemical B. Why - well because he could. We investigated further understanding the actual sequence of what happened. The two chemicals were ordered from the same supplier. they had really chemical names that the receiver didn't understand. the names were very similar. in fact, they were exactly the same for the first dozen or so characters. The lot number and part number on the supplier label were different from the lot number the company assigned (We pre-assign lot numbers for this class of chemicals after a pre-shipment qualification test) and the part number that we ordered against (part numbers are different for difference suppliers for this commodity level class of chemicals.) Chemical B came in first. The receiver put the A label on and received the part against the A line item on the PO. Of course when Chemical A came in the only line item available was for chemical B so A got B's label and voila! two bad things. Now the manager of the area wanted to discipline the operator saying that if he was unsure he was supposed to set it aside for someone else to figure it out. I asked the manager to go observe receiving during the same time frame as when the label mixup. he came back after an hour and said "wow. it's a miracle they get any label correct." the speed of receipts is incredible and there is very little room to hold material in the area or on a truck. it 'must' be moved quickly into the assigned storage area to allow for more stuff to offloaded form the trucks and received in and moved. chaos is a goo description. Clearly the organizational factors of 'receive the parts quickly' and the cramped workplace conditions along with the part number. lot number disparity and a very long nonsensical chemical name conspired to result in the action of mislabeling the first chemical. the latent condition of the wrong received line item led to the second chemical being mis-labeled. We had to make a couple of changes: we made it impossible to have a PO for certain types of chemicals that come from the same supplier and have similar names on the same PO. (the purchasing manager was initially opposed to this but the buyer really liked the change - said it made his job a lot easier.) Then we also had our ERP system change to use the same part number as whatever the supplier used and we eliminated the company specific lot number assignment. then the PO and the Label had the same information... It didn't really take that long (the error was quite expensive though) to get to a real solution once we moved people away from blaming others and carping that the operator needed to have better discipline or whining that we would never eliminate all errors. Someone wanted to implement a separate inspection for the labels; it didn't work because all of the conditions that led to the original mistake were still on place. and the error rate was actually very low so that the 'inspectors' rapidly became complacent.

The issue people have about claiming operator error and then offering training or discipline as the corrective action is that it is a very shallow understanding with a very shallow correction action that simply isn't effective...
That's great and an effective way to handle these types of mistakes. However, it doesn't "guarantee" that a similar mistake won't happen again. And that is where many people get hung up. With everyone focusing on "zero defects" IMO it's impossible if the human element is at all present.
 
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