Improvement Insights Blog
Why Are People Using Line and Bar Charts, not Control Charts?
If you look at improvement project posters at quality conferences around the country, you’ll find that almost everyone is using Excel line and bar charts. Even after decades of Six Sigma training and association membership. What’s the hold up? Here’s my take:
“Hi, I’m Jay Arthur, author of “Lean Six Sigma Demystified” and QI Macros [software].
“Every year I look at lots of improvement posters and I keep wondering, “Why isn’t anyone using the tools of Quality?” Control charts, Pareto charts, histograms… Most of them are just using plain old Excel line and bar charts. Now it might be because they don’t know about the power and beauty and how easy it can be now to do Control charts, Pareto charts and fishbones. Maybe it’s just laziness, you know? “Well, I’d have to go buy a software package and then I’d have to learn how to use the software and then I’m not sure it would do the right thing…”
“I’m not sure it’s any of those things. I think the number one thing stopping people is fear. What do I mean by that? Well, they’re afraid, “Well, if I pick a control chart, someone might challenge why I picked that control chart.” I see this way too often. That’s why I know this is a problem.
“A very long term client called up and said, “Well, can we use control charts for percentages? I wanted to use them for percentages and somebody said you can’t use control charts for percentages.” Of course you can! That’s nonsense. You can use an XmR chart. If you have the numerator and denominator you can use a p chart or a u chart. It’s easy, all right? Somebody thought they were uber smart and said, “I heard somewhere that you can’t use them for such-and-such.”
“And so people hesitate; they stop. So I think the fear is out there. And I think that’s because Stat Bastards want to lord their expertise over everybody, and it’s like, “Oh, stop!” Let’s get people using them, and then we can make them uber smart about which chart to choose.
“I’m telling you, way back in 1999 Pyzdek said the XmR chart is for individuals data of any kind. Dr. Donald Wheeler says the XmR Individuals chart is the absolute Swiss Army knife of control charts. I’m going to suggest to you, why not just start learning how to use one chart: the XMR chart for individuals data, in service industries or manufacturing. Any time you have an individual column of numbers, let’s start using that. Let’s figure out and get used to it.
“I made lots of mistakes when I started, and maybe I was wrong; I’ll get better next time. Shut up! Leave me alone! Do you have better data? Have you run the charts? No, they’ve never run the charts. They’re just blathering because they don’t want to have to put up with a new something that THEY have to learn like a control chart. Leadership teams do this all the time as well.
“So let’s overcome the fear and let’s just start using the Tools of Quality, because next time I go to health care Quality conferences or American Society for Quality conferences or any other Quality conference and I see line and bar charts, I’m going to think that people are still afraid.
“I’m Jay Arthur. That’s my Improvement Insight for this week. Let’s go out and improve something.”
