By: Davis Balestracci
03/22/2011
When teaching the I-chart, I’m barely done describing the technique (never mind teaching it) when, as if on cue, someone will ask, “When and how often should I recalculate my limits?” I’m at the point where this triggers an internal “fingernails on the blackboard” reaction. So, I smile and once again say, “It depends.” By the way…
… Wrong question!
I made a point in Part 1 of this article that I feel is so important, I’m going to make it again: Do not bog down in calculation minutiae. If you feel the instinct to ask that question, pause and think of how you would answer these from me instead:
1. Could you please show me the data (or describe an actual situation) that are making you ask me this question?
2. Please tell me why this situation is important.
3. Please show me a run chart of these data plotted over time.
4. What ultimate actions would you like to take with these data?
And since writing Part 1, I’ve thought of a fifth question I’d like to add:
5. What “big dot” in the board room are these data and chart going to affect? Or less tactfully,