“…That is, an A at an "easy" school is not equivalent to an A at a "hard" school. \{hile this is an important problem as evidenced by the large number of papers in the literature (e.g., Bloom & Peters, -3-1961;Hills, 1972;Lindquist, 1963;Tucker, 1963), it is not dealt with in this paper. Before such grade adjustments for ability variation among schools can be performed, it is necessary to convert reported grades to some common numerical system.…”