>New data shows studying for the SAT for 20 hours on free Official SAT Practice on Khan Academy is associated with an average score gain of 115 points, nearly double the average score gain compared to students who don’t use Khan Academy. Out of nearly 250,000 test-takers studied, more than 16,000 gained 200 points or more between the PSAT/NMSQT and SAT …

https://www.washingtonpost.com/news/answer-sheet/wp/2017/05/...