1. A method comprising: employing a computer for quantifying optical proximity correction (OPC) model accuracy by performing operations comprising selecting an OPC model at least by performing quad matrix management which comprises obtaining wafer data from a calibration test pattern, classifying the same wafer data obtained from the calibration test pattern into four quadrants of a quad matrix, and utilizing one of the four quadrants to quantify OPC model accuracy; creating a photomask based at least in part on the selected OPC model after performing the quad matrix management; performing wafer verification; and verifying lithography performance.