I totally agree that control charts are the best way to display and understand process data. (Interesting that Wheeler used control chart format to compare the home run hitting of Mantle and Maris in his book "Understanding Variation")

And I like constructing the final chart to show some manner of shift around 2012. I still don't feel like I understand what it was that changed then, but it seems clear that we went from one stable range of performance, to another stable range.

The display of velocity vs. year does not appear to help, given that it's a steady-ish trend with 2012 smack in the middle of it.

But I hope Dr. Wheeler will appreciate the use of "process behavior" charts.