Question: Am I Recalculating the Limits Correctly?
Reader question: “When you are recalculating the average because you see a shift, does the average from your previous calculation only take into account those
Blog: Reader Questions
Question: Why Use 25 Data Points for the Average & Limits in the Template?
A question: I have a question about the formulas for columns C & E in your template. Is there a reason they’re set to only
Question: Does the System Need to be “In Control” to Get Started?
A question: Hi Mark — long time reader, first time sending a question…. I love your recent emphasis on eliminating “red/green” analyses, and moving toward
Question: Do I Need Normally Distributed Data to Use a Process Behavior Chart?
Question: To have a valid control chart (or “Process Behavior Chart”), don’t I need data that’s normally distributed? In other words, a “bell curve”? Short
Question: A Lower Limit Below Zero?
Question from a reader: As we know sometimes when we calculate the Natural Process Limits, the Lower Limit is negative. In some measures, that’s not
Question: Is it Appropriate to Plot Averages on a Process Behavior Chart?
I’ve gotten this question a few times recently, basically asking if it’s OK to plot metrics like these on a Process Behavior Chart (PBC): Weekly
Question: Why Are There Different Ways of Expressing the Formulas for the Limits?
Here’s a good question from a reader: In your KaiNexus webinar on PBCs you use: LCL = Mean – 3*(MR bar)/1.128 and UCL = Mean
Question: Why are the Limits so Wide?
A reader shared a Process Behavior Chart with me and asked this: “On the Falls_Harm tab, the limits seem a bit far away from the
Question: Why are There so Many Data Points Outside of the Limits?
I got a message from a reader of my book Measures of Success: React Less, Lead Better, Improve More. The questions were: “I entered data from
Question: How Can I Add More Data Points to a Process Behavior Chart?
A question that a few people have asked: “Your PBC template, by default, only shows 25 data points. How can I add more points to
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Hi. I'm Mark Graban
I help businesses leaders and workers improve their activities and processes. With methods grounded in Lean, math and science — backed by data. Better to make choices based on facts — instead of opinions, hunches, or feelings. Learn how to convert data, metrics, and charts into knowledge and wisdom — to drive more improvement. That’s what I do and why I wrote "Measures of Success."
