XmR chart – Lean Six Sigma Moneybelt

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Posts tagged "XmR chart"

Start Using XmR Charts for All of Your KPIs

Do you spend too much time chasing why one number is too high or another is too low? Are these kinds of wild goose chases wasting time while the real problems go wanting? The XmR chart is the answer to your dreams.

“Dr. Donald Wheeler calls the XmR chart (or Individuals and Moving Range chart) “the Swiss Army knife of control charts.” You can use it for all kinds of things.

“I believe if every company in America started using XmR charts to track all of their key process indicators, I don’t care if it’s financial results or defects or patient length of stay or I don’t care what it is.

Posted by Jay Arthur in Improvement Insights, QI Macros, Statistics.

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.

Posted by Jay Arthur in Improvement Insights, Lean, Six Sigma.

2020 New Years Resolution Part 1 – Learn One Tool Per Month

Many people tell us that they have QI Macros, but they don’t know how to use it. Make a resolution to learn how! Here are my suggestions.

“Hi, I’m Jay Arthur and… it’s 2020. How did that happen? A new year; a new decade. Seems like just yesterday everybody was worried about Y2K. Somebody out there is thinking, “What’s Y2K?” That was a thing that happened back in the year 2000… you probably forgot all about it, but I’ve been at this for over twenty years now in the software field around Quality Improvement, so I’ve seen a lot of things.

Posted by Jay Arthur in Improvement Insights, Lean, QI Macros, Six Sigma.

Use XmR Charts instead of c, np, p and u Charts

I have found that an XmR chart is the easiest way to display attribute data. Simply convert the numerator/denominator into a ratio and plot the ratio.

  • defects per day could be a c chart, but an XmR chart works just as well
  • defects/samplesize could be np, p or u chart, but XmR chart works just as well using the ratio

Almost two decades ago, Tom Pyzdek said: X chart provides an excellent approximation to the p chart.

More recently, Donald Wheeler noted that XmR chart limits will be very close to c, np, p or u chart limits if the underlying distribution is correct.

Posted by Jay Arthur in QI Macros, Six Sigma, Statistics.