A method for determining a lateral offset of a pattern on a substrate relative to a desired position with the steps: a) providing a plurality of measurement and simulation images of the pattern with equidistant defocus positions, b) forming a plurality of first and second pairs, which each has a measurement image and a simulation image, wherein each first pair has the same first focal distance and each second pair has the same second focal distance, being different from the first focal distance, of the defocus positions thereof, and determining a first and second lateral distance of the patterns for each first and second pair, respectively, c) determining a first and a second linear fit line based on the determined first and second lateral distances, respectively, and d) determining the lateral offset of the pattern on the substrate relative to the desired position using the linear fit lines of step c).