There is a burgeoning body of evidence on the average impacts of educational programs. Yet, for many local decision makers, because impacts can vary across sites, the question of whether a certain program will work in their particular district or school remains. This article addresses the question of the generalizability of large-scale average…

Teachers spend most of their time in school in classrooms, and their instruction and teaching practices may be affected by classroom context such as class size. We examine whether teacher effects interact with classroom context such as class size. Specifically, we seek to determine whether teacher effects are more pronounced in small classes than…

Thus far researchers have focused on computing average differences in student achievement between smaller and larger classes. In this study, the author focus on the distribution of the small class effects at the school level and compute the inconsistency of the small class effects across schools. The author use data from Project STAR to estimate…

Through a synthesis of test publisher norms and national longitudinal datasets, this study provides new national norms of academic growth in K-12 reading and math that can be used to reinterpret conventional effect sizes in time units. We propose d' a time-indexed effect size metric to estimate how long it would take for an "untreated"…

Pupils (N=1,755) in 232 elementary school classes in Tennessee participated in a 3-year longitudinal study of the effects of reduced class size on reading and mathematics performance. The small-class setting increased performance significantly in both mathematics and reading, and it had an especially strong impact in inner-city schools.…

During the 1989-90 school year, Tennessee established Project Challenge in 17 of Tennessee's poor and educationally low-performing counties. The program applied the results of Project STAR, a longitudinal experiment causally linking class size to student achievement. This paper presents findings of a study that evaluated Project Challenge by…

Between 1985 and 1989, the Student Teacher Achievement Ratio (STAR) Project studied the effect of class size on student achievement in Tennessee schools. The study examined: (1) small classes of 15 students per teacher; (2) regular classes of 24 students per teacher; and (3) regular classes with a teacher's aide. The sample included students from…