In simplest terms, we compare average student achievement gains in the same school under different principals. (educationnext.org)
Overall average student achievement in grades 4 and 8 in both reading and math has grown over the longer term, showing annual improvement in most years. (thelearninglandscape.org)
In four states, there is not a single traditional district with average student achievement above the 50th percentile in math. (educationnext.org)