A Lesson in Variation
I love this dialogue between Daddy and Daughter. People who know me will recognize me in there somewhere. I am not a chemistry professor, but I did spend 30 minutes recently trying to explain the concept of process variaton to my daughter Girlzilla who keeps missing the bus, requiring a ride from me.
I started charging her $30 per ride. She was outraged. So I explained to her:
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Think of all your morning out-the-door times as a population that has an average and a standard deviation
Not all of your out-the-door times meet standards (you miss the bus)
You can look at your morning prep from waking time to walking out the door as a process that produces this critical measure — out-the-door time
You can choose to change your process to make your average out the door time earlier, allowing for your current level of variation in your morning prep process (scoot the average)
You can choose to change your process to reduce the variation in your process (be more consistent) thus allowing you to have the same average, but make the bus more consistetly (squish the standard deviation)
But I admit change is painful. Especially if it involves getting up earlier in the morning
So you can also decide to live with a certain amount of non-conformance (missing the bus)
Apparently you have been deciding that the considerable pain of change is greater than the incovenience of missing the bus for you
But you have not accounted in your considerations the inconvenience to me
So I am charging you $30 (or six hours of babysitting) for each ride, thus shifting the pain back to you so you can make an informed evaluation of your morning preparatory process results
Now that your non-c0nformances are sufficiently painful, you can do any combination of three things:
Wake up earlier or do something to “scoot” your average ready time earlier, thus making it to the bus in time
Streamline your process to reduce the variation, allowing you to wake up at 6:15 and leave by 6:40 on a consistent basis and still make the bus in time
Or pay me for each non-conformance
Now you get to make the decision of how much money you wish to spend to avoid the pain of change, and thus I am treating you like an adult
Having explained everything so well, can you be surprised that she still was not convinced? Apparently my logic “Sucks.” But her on-time performance went up over 80% over the next month. So Daddy does know best. Heh.

