This note implements two research designs that attempt to isolate the effect of class size on achievement. A first strategy focuses on variation in class size in rural schools with fewer than 30 students, and hence only one classroom, per grade. Second, an approach similar to Angrist and Lavy's exploits regulations that allow schools with more than 30 students in a given grade to obtain an additional teacher. Both designs suggest class size negatively affects test scores.

We examine student, teacher, and peer perceptions of effort, ability, performance, and self-confidence in Romania's highly tracked schools. We find that: (1) students just above a cutoff—tracked into high-achieving classes—have less favorable self-perceptions than those just below (“big-fish-little-pond” effects); (2) students perceive peers in their classes more favorably (“in-group bias”); (3) this bias is stronger in lower-achieving classes; (4) students perceive themselves more positively than others perceive them (“illusory superiority”); (5) this bias is stronger among lower-achieving students (“Krueger-Dunning effects”). In short, being tracked into lower-achieving classes does not appear to negatively affect self-perceptions.