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 Press Ganey patient satisfaction responses (12-month running totals) and since the numbers were so close to each other, the PBC showed a bunch of data points outside the upper/lower process limits.
When I changed the limits to +- 3 sigma, this issue disappeared. Have you run into this issue before? Can you help me to understand the difference and its impact on analysis using the PBC?”
Read more and see my answer and analysis here:
[Updated] Reader Question: Why are There so Many Data Points Outside of the Limits?