In 1959, the American Institutes for Research (AIR) and the University of Pittsburgh selected a stratified random probability sample of all secondary schools (public, parochial, and private) in the United States, tested all their students in grades 9-12 with a two-day battery of aptitude tests, information tests, tests of ability and achievement,…

Recent investigations of the extent to which students with disabilities are allowed to participate in major national data collections used in measurement-driven education reform suggest that 40 to 50 percent of students with disabilities are typically excluded from major assessments, although they are included to a greater degree in assessments…

The utility of the biomedical model of adjusted statistics is demonstrated. The model is recommended for use by educational researchers to randomize subjects for a more accurate estimate of school programs' success or failure when compared across classrooms or other units. (Author/MH)