Is 'Operator Error' as Root Cause ever acceptable?

Jennifer Kirley said:

...Such things come with experience, one would think - learning when and where to not fiddle with stuff.

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That is that part i was keying into. In relation to ISO, we discover weak points by analysis or by experience, then those observations should be turned into control points wherever practicable, to provide better control in the future. An example is the GPS unit in a Hertz rental car flashes a message to not use it if the car is in motion (of course, it then let's you go ahead and use it anyway - not very robust).

But I also once read that most accidents occur within 25 miles from home (like this one). Familiarity is said to play a role, also just not being mentally engaged....

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I have often wondered if the cause for this statistic being true is simply because most trips are within 25 miles from home also.

Helmut Jilling said:

That is that part i was keying into. In relation to ISO, we discover weak points by analysis or by experience, then those observations should be turned into control points wherever practicable, to provide better control in the future. An example is the GPS unit in a Hertz rental car flashes a message to not use it if the car is in motion (of course, it then let's you go ahead and use it anyway - not very robust).

I have often wondered if the cause for this statistic being true is simply because most trips are within 25 miles from home also.

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When the phone refuses to allow texting while the car is in motion, we'll be rich!

If it's true that most accidents happen close to home (I'm not sure) no doubt one big cause for the number is the number of trips made nearby.

Entirely correct! Root causes are almost always a systematic failure. As stated, this could be lack of training or lack of approriate procedure, a procedure known but not followed or even a mis-understood procedure.

So right, Mike! We can't make everything idiot proof!

aliasJohnQ said:

So right, Mike! We can't make everything idiot proof!

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Are you (seriously) suggesting that an organization goes out and employs idiots? Maybe it's just a joke...

Since this thread has been resurrected, it occurs to me that the 4 stages of adult learning have been overlooked (I didn't read the whole thing through to see if anyone had raised that before).

Anyone who understands how adults learn to do work etc. will be familiar with these 4 stages:

Unconscious incompetence, conscious incompetence, conscious competence and unconscious competence. We all go through such stages and each one is not a concrete stage, we can 'slide' back from being 'the best' to being the worst at a job, especially if something changes!

operator error may be one of the root cause but we need to focus on mistake proofing why mistake had happened and take steps to avoid manual intervention. Ideally defect shall not be produced even though operator done mistake.

Ha Ha Ha --- this is a test right..... And the permanent corrective action would be to fire the operator.

I have a case where we have molded well over a million parts with zero defects for over six months. Several defective parts were found at our customer and we have determined that the reason the parts escaped was that a trained operator, who has done the job correctly for months, failed to scrap the required number of start up shots were the defect - short shots occurs.

He admits he did not follow procedure.

The occurrence of shorts at a start up cannot be eliminated, it is essential that parts not be saved until start up parts are purged.

IS the root cause operator error?
If it is not, how do you mistake proof this type of situation?

yes the cause is operator error. However, the solution that won't work is to train them, admonish them or discipline them. The underlying causal mechanism of 'operator error' is that the system allows them to make the error or mistake and so they will. It is fundamental human nature. (and why we invented spell checker - I can spell perfectly well, I just can't type the letters in the order they were intended to be typed )

So mistake proofing is the appropriate corrective action if you must reduce the defect rate. Most error proofing schemes are relatively cheap if you put some thought into them.

A place ot start in this situation is to determine why the operator didn't follow the procedure - is it too complicated? did he deliberately choose to not follow it? if so why? did he really not understand the consequence of short shots beign shipped to the customer or did he think his supervisor was more interested in quantity than in quality? Perhaps he thought that there weren't that many short shots and he was saving the company money? (there is a slight difference between unintended errors and intentional mistakes)
these questions can provide insight into what steps will work to prevent the occurence in the future...

some simple tools that help ensure that the start up parts are culled and scrapped: if there is a set number of shots to successful startup, have a 'bin' that either counts (thin egg carton) or weighs (depending on size) the startup parts and this bin must be filled and accounted for before parts can be moved into the 'good' bins or stream. perhaps a simple countere can be used to manage a diverter switching from the startup scrap stream to the good stream once a specific count has been reached? But the best approach that I've found is to ASK the employees how they think the process can be improved....

Bev D said:

But the best approach that I've found is to ASK the employees how they think the process can be improved....

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Good to see that someone has got some good internal customer focus.

When considering why staff make 'operator error' it would'nt hurt to consider factors such as workloads, how interesting the job is, how much self management is involved in the task and the culture in the workplace concerned. However; I appreciate these kinds of issues cannot be given as explanations to customers.