1. A computer implemented method for simulating the performance of a system represented hierarchically as a top level system operably interconnecting a plurality of subsystems, comprising: identifying a set of input variable values for each subsystem in the plurality of subsystems; simulating a first subsystem in accordance with a corresponding first set of input variable values to generate a first plurality of design points, wherein each design point represents a performance result of the first subsystem based on the first set of input variable values; generating a centroid for representing a first subsystem performance result using the first plurality of design points, wherein the centroid is numerically calculated based on a plurality of the first subsystem performance goals; simulating the top level system using the centroid to generate a first performance result of the top level system; and storing the first performance result of the top level system in an information storage media.