A method of determining a position of a feature (for example an alignment mark) on an object (for example a silicon wafer) is disclosed. The method comprises determining an offset parameter, determining the second position; and determining a first position from the second position and the offset parameter, the position of the mark being the first position. The offset parameter is a measure of a difference in: a first position that is indicative of the position of the feature; and a second position that is indicative of the position of the feature. The offset parameter may be determined using a first measurement apparatus and the second position may be determined using a second, different measurement apparatus.