Use overlaid contour plots to jointly evaluate multiple responses. Minitab draws contours for each response and overlays them on top of each other in a single graph. Overlaid contour plots can help you identify variable settings that optimize a single response or set of responses.

Contour plots for response surface designs show how response variables relate to two continuous variables while holding the rest of the variables in the model at fixed settings.

A company developing a new tire tread compound studied the effects of three ingredients on four responses. The three ingredients are Material A (Mat A), Material B (Mat B), and Material C (Mat C) The four responses are Abrasion, Modulus, Elongation, and Hardness.

Data source: G Derringer and R. Suich (1980). "Simultaneous Optimization of Several Response Variables," Journal of Quality Technology, Vol 12, pp.214-219.

Data: TireTread_model.MTW (available in the Sample Data folder).