The stronger the emphasis on academic courses, the more advanced the subject matter, and the more rigorous the textbooks, the more high school students learn. Subjects that are learned mainly in school rather than at home, such as science and math, are most influenced by the number and kind of courses taken.
Students often handicap their intellectual growth by avoiding difficult courses.
The more rigorous the course of study, the more a student achieves, within the limits of his capacity. Successful teachers encourage their students' best efforts. An Analysis of Textbooks in Relation to Declining SAT Scores. Col- lege Entrance Examination Board. A Review of IEA Evidence.