„The typical student in Asia attends several types of schools simultaneously. […] In Korea for instance, 88 % of the elementary students and 61 % of the students in general high schools receive private tutoring in cram schools.“
Univ.-Prof. Dr. Stephen Heyneman, „The International Efficiency of American Education: the bad and the not-so-bad news“ in Meyer u. a., „PISA, Power und Policy“ (2013), S. 294