By Dr. Marciene Mattleman

PHILADELPHIA (CBS) - New research by professors from Stanford, Harvard and the University of Munich was released under the auspices of the Program on Education and Policy at Harvard.

Using data from the National Assessment of Educational Progress, referred to in an Education Week Ed Watch blog, as the “gold standard for measuring achievement,” they dealt with student improvement, not just scores.

Looking at performance from 41 states in the study, Maryland did best in score gains. Student achievement in math, reading and science improved more than two years of learning from 1992 to 2011.

Five of the top ten states were in the South and no southern states were among the 18 slowest-improving. Authors noted in these states governors provided much of the national leadership for school accountability spurred by civil rights legislation.

While the report brings some good news, it also compared achievement gains by Brazil and Germany to the U.S. and found us mediocre and barely keeping up.