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)

The authors have written this manual to aid workers in the Cooperative Extension Service of the United States to be better able to understand and apply the principles and methods of evaluation. The manual contains three sections which cover the nature and place of evaluation in extension work, the evaluation process, and the uses of evaluation…