 In the 2015-2016 academic year, 75 percent of Walden high school students had taken at least one AP exam.In 2009, according to the website, Lower School students taking the Stanford Achievement Test averaged in the 81st percentile in Reading and Math, and the 85th percentile in Science.This means that Walden students scored in the top 19 percent nationally in Reading and Math and in the top 15 percent in Science.