Fig. 1
From: Equal opportunities for all? Analyzing within-country variation in school effectiveness
Schematic illustration of the regression discontinuity approach. Figure displays the results of the regression (dashed line) of achievement scores (y-axis) on age in months (x-axis) and an added year of schooling in a sample of students (grey dots) from two adjacent grades. Within grades, the slope reflects the effect of age. The discontinuity in the regression reflects the effect of an added year of schooling