Especially to your wife.
So even if readers didn’t leave comments I still had to face the error of my logic on the post “please arrive 15minutes before your appointment”. Her comment was, “if I arrive 15minutes before my appointment that’s just 15minutes more I have to wait”.
Which creates a catch 22. If your clinic is hopelessly late with patients it’s unlikely they’ll willing show up 15minutes early. If you require 22 +/- 7minutes to prepare the patient for the visit you’ll constantly run 22 +/- 7 min late. You can’t win. Or can you?
The answer is to control the variation before you control the arrival time. If one clinic operates 22 +/- 7 minutes late, arrival time can be gradually changed. If it runs 22 +/- 30minutes late a significant portion of your patients are waiting greater than 52 minutes. Why would they arrive early?
The answer to the dilemma is not in looking at the average and variation per say, rather, examining the number of outliers. The technique goes back to my posts on six sigma in the office to minimize office wait times. The suggestions to my wife’s doctor are to first control the variation in the arrival times, then control the actual arrival time.