Overview of the Scaling Methodology Used in the National Assessment.

The National Assessment of Educational Progress (NAEP) was designed to report what students in American schools, both public and private, know and can do. Obviously, not all of the proficiencies of students can be assessed, and so a sample of exercises in school subject areas is selected to represent the overall proficiencies of students. The selection of exercises is very important, and NAEP selects the exercises using a consensus approach. A large committee of learning area specialists, educators, and concerned citizens is formed for each subject area assessed. These learning area committees specify the objectives for the assessment in terms of what students should achieve during the course of their education. The objectives for a subject area are typically defined in terms of a content-by-process area matrix for which the approximate percentage of items of each type is specified by the learning area committee. In order to satisfy the objectives of the assessment and ensure that the tasks selected to measure each goal cover a range of difficulty levels, NAEP samples