Length Out of Specification - How do I perform Cause and Effect Diagram?

If I have detected a trend in nonconformances regarding dimensional issues. I.e. length out of specification. How do I perform cause and effect? I identify the problem, then ask the question "How did the length become out of specification?" and the answer would come back, "Operator error" As we know, 99% of the time its the method, measurement and so on, and not the operator. What I'm trying to achieve is, what category would I identify in the cause and effect? Can it be more than one category? Thanking you in advance

Re: Cause and Effect

Not sure if this is the answer your looking for, but when they say "operator error" you asked "why", which in my experance will generate "He was not paying attention". I then asked "Why?" again. I keep the why's up till I get past the 'operator error'.

Re: Cause and Effect

Can the issue be in other area's when doing cause and effect? Example:As per our discussion, we they say Operator error. This would start at people. Once it gets past that could it go to another category? Would you have an example of a cause and effect I could look at? Appreciate your time and help in this, Michael!

If you are detecting "a trend in noncorformances" that implies you are collecting data. Before you ask the cause, you may want to share that information with the worker/manager and ask them if there could be any machine issues.

Bill Pflanz

how do you 'know' it's operator error? what data do you have to support that conclusion?

Of course causal mechanisms move between categories of the various M categories - it is but one reason I do not use 'fishbone' diagrams.

Re: Cause and Effect

Michael_M said:

Not sure if this is the answer your looking for, but when they say "operator error" you asked "why", which in my experance will generate "He was not paying attention". I then asked "Why?" again. I keep the why's up till I get past the 'operator error'.

Click to expand...

i agree... just use the 5 WHY and maybe you can get to te bottomline

Re: Cause and Effect

5 whys is a good way drill down for root cause, try to do a MSA where Appraisal and Measurement system need to be analysed. Some time you will find that "operator error" is not significant as root cause may be are other systematic issues involved that create operator errors.