For example, the top quarter of elementary - school teachers improve student achievement in math by 33 percent of a standard deviation more than the bottom quarter of teachers do. (educationnext.org)
To assess overall performance, we identify the percentage of students in the high school class of 2015 who are performing at proficient and advanced levels of achievement in math. (educationnext.org)
As I note there, toy blocks are linked with better language development and higher achievement in math. (parentingscience.com)