1. A computerized system for evaluating design changes to a computerized model, comprising: a computer programmed to: conduct finite element analysis on a quantity of interest for a base design of the computerized model to determine a primary field; derive an adjoint field for the quantity of interest of the base design; accept an input for a design change of the computerized model from a user; determine a performance metric of the design change for the computerized model as a function of the primary field and the adjoint field without finite element analysis of the computerized model as modified by the design change; and output the performance metric to an electronic display; wherein the performance metric is a range of values representing a lower bound for the performance metric and an upper bound for the performance metric based on the effect of the design change.