In the US, by contrast, credentials signifying time spent in school are well rewarded but most students realize few benefits from studying hard while in school. (p.3)
Admission to selective colleges is not based on an absolute or external standard of achievement in high school subjects. It is based instead on aptitude tests which do not assess the high school curriculum and on such measures of student performance as class rank and grade point averages, which are defined relative to classmates' performances not relative to an external standard in the way scout merit badges or the English '0' level exams are.
The peer group actively discourages academic effort because studying hard shifts the grading curve up and makes it harder for classmates.
Parents do not demand higher standards because this will not improve their child's GPA, rank in class or SAT score and it would put at risk what is really important--the diploma.