A method of evaluating a patterning process, the method including: obtaining the result of a first measurement of a first metrology target; obtaining the result of a second measurement of a second metrology target, the second metrology target having a structural difference from the first metrology target that generates a sensitivity difference and/or an offset, of a process parameter of the patterning process between the first and second metrology targets; and determining a value pertaining to the patterning process based on the results of the first and second measurements.