1. A method comprising: receiving a first amount of measurement data associated with measurements of a first plurality of sites on a surface of a semiconductor wafer with known variations of at least one process parameter, structure parameter, or both, wherein the first amount of measurement data is derived from measurements performed by at least one metrology technique; determining an expected response model of each of the at least one known process parameters, structure parameters, or both; determining an input-output measurement model based at least in part on the first amount of measurement data; and training the input-output measurement model based on parameter values determined from the expected response model.