Its "Why tough teachers get good SAT scores" not good education results.
SAT scores are mentioned exactly once in the article (well, twice, but in reference to the same finding), I have copy-pasted it for your convenience:
> When she applied the ["Grit Scale"] to incoming West Point cadets, she found that those who scored higher were less likely to drop out of the school's notoriously brutal summer boot camp known as "Beast Barracks." West Point's own measure—an index that includes SAT scores, class rank, leadership and physical aptitude—wasn't able to predict retention.