Children do better all through their schooling, he declared, if by fourth-grade they have spent just one year in a class of only 15 students. Poor children in particular are helped by early attention from a teacher. I infer that very young children become socialized in a small class. They learn how to behave in school. They are more likely to take the SAT exams in high school, and to earn more later as workers.
Empirical economists talk that way, as if each finding is a nugget of fresh, significant insight.
No group within the profession is challenging accepted wisdom more vigorously. But Krueger does so rather cautiously. For all his enthusiasm, he is reluctant to prescribe small classes as national policy without more research. There is a reason for his hesitation. Empirical economists may be increasingly pressing theorists, but abstract thinkers still dominate academic economics with their explanations of how people and markets behave.