When the Educational Testing Service became the administrator of the National Assessment of Educational Progress (NAEP) in 1983, it introduced scales based on item response theory (IRT) as a way of presenting results of the assessment to the general public. Some properties of the scales and their uses are discussed. Initial attempts at presenting…

Evaluators usually assume that the data they receive are valid, or at least, that the data reflect that which is being evaluated. In a recent evaluation in a large southern school district, evaluators compared their raw interview notes with interview notes edited by the teachers interviewed or project staff. The program evaluated was Project SEED,…