There's a lot of evidence that it's difficult to drastically change someone's test scores in a year or two, and it's compounded by the degree of internal motiva

There's a lot of evidence that it's difficult to drastically change someone's test scores in a year or two, and it's compounded by the degree of internal motivation of the test taker. And there's an element of reversion to the mean with children of some high achievers. Meanwhile, GPA and extracurriculars are significantly reflections of socialization and parents rather than anyone's inherent or learned abilities.