Abstract: A method of making ceramic bodies having reduced shape variability. Such ceramic bodies include extruded-to-shape substrates and diesel particulate filters. Principal components analysis is used to generate a small number of uncorrelated or independent components from a larger set of inter-correlated measurements. The uncorrelated components can then be used during the forming process to control the shape of ceramic bodies and reduce variability of such shapes. A method for quantifying and subsequently reducing the shape variability of is also described.