I have a set of design points that were previously run, and I would like to compare to a custom DOE design for the same variables. The design should be assessed as a split-plot since one of the parameters was not randomized due to its difficulty to change. When I label the variable as "hard" to change and run the DOE>Evaluate Design - I get an error stating that I need to add the Whole Plot factor if I have a hard to change factor. I added a Whole Plot column associated with the changes to my hard-to-change factor, but I am still recieving the same error. Please advise me on how I can evalauate historical data as a split-plot design?