A method for determining a correction to a patterning process. The method includes obtaining a plurality of qualities of the patterning process (e.g., a plurality of parameter maps, or one or more corrections) derived from metrology data and data of an apparatus used in the patterning process, selecting, by a hardware computer system, a representative quality from the plurality of qualities, and determining, by the hardware computer system, a correction to the patterning process based on the representative quality.