The purpose of this study was to determine whether a Mexican version of the Peabody Picture Vocabulary Test could be improved by directly translating both forms of the American test, then using decision procedures to select the better item of each pair. The reliability of the simple translations suffered. (Author/BW)

In an attempt to restore the symmetry and balance between the study of person and item variation, this paper presents a novel methodology construct specification equations, which allows one to ascertain from the lawful behavior of items what an instrument is measuring. (Author/PN)