Histogram Interpretation when a process is "running too high" or "running too low"?

Re: Histogram interpretation?

gel270 said:

I hope this is the appropriate forum, my apologies if it isn't.

In interpreting a histogram for my process, my guide book is telling me my process is "running too high". Could someone please explain what it means when a process is "running too high" or "running too low"?

Thank you!

P.S. This is a great web site that has offered me endless guidance throughout my green belt certification! Thank you!

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What's the process? What's the guide book? In general, "too high" means there's some form of danger of exceeding the upper specification limit, and of course "too low" means the opposite. A histogram is generally not a good tool for making confident pronouncements about process efficacy, though.

Re: Histogram interpretation?

I’m analyzing our process for responding to a customer that has submitted a complaint. I’m looking at cycle time. Among using many other Six Sigma tools, I was using the histogram to graphically show the frequency of how often we our “off” our target cycle time.

My class materials were a little vague, so I was relying on my Six Sigma Memory Jogger II pocket guide to help me with use of this tool. Based on how the distribution was centered, it looks like my process is running “too high”. Your explanation that there is danger of exceeding the USL makes perfect sense here. Thank you!

Re: Histogram interpretation?

gel270 said:

I’m analyzing our process for responding to a customer that has submitted a complaint. I’m looking at cycle time. Among using many other Six Sigma tools, I was using the histogram to graphically show the frequency of how often we our “off” our target cycle time.

My class materials were a little vague, so I was relying on my Six Sigma Memory Jogger II pocket guide to help me with use of this tool. Based on how the distribution was centered, it looks like my process is running “too high”. Your explanation that there is danger of exceeding the USL makes perfect sense here. Thank you!

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You should be able to tell what's going on just from looking at the numbers unless you have an awful lot of customer complaints to track. Even a simple line graph would probably be better than a histogram. You shouldn't drag out a bunch of tools just for the sake of using them, or let the tail wag the dog.

Re: Histogram Interpretation when a process is "running too high" or "running too low

Haha! I agree Jim! However, I'm required to utilize a certain number of tools for each phase of the DMAIC methodology to get my certification. I believe my instructor knows the tool isn’t necessary, but he wants to make sure that I can apply the data to the tool and that I understand what the tool is used for and what it’s telling me. I sure do appreciate your practical advice!