What comes to mind when you think of “return on investment?” For most of us, our mind jumps to calculations of costs and revenues. The end goal, no matter the project, is for the last cell in the spreadsheet to be black or green—not red.

Recently, Mary Doyle Keefe passed away at the age of 92. You may not recognize her name, but you’ll definitely recognize her face. Keefe was the model for Norman Rockwell’s famous 1943 painting, Rosie the Riveter.

If it didn’t work then, will it work now? Elephant syndrome is what I call it, the tendency to never forget. But I’m not referring to a good memory; I’m talking about a faulty forgetter.

While the computations for a process behavior chart are completely general and very robust, the secret to using a process behavior chart effectively lies in the art of rational sampling and rational subgrouping.