The Saint Paul school board and teachers union host a reception this afternoon to honor the district's 28 teachers who've earned certification from the National Board for Professional Teaching Standards. Saint Paul leads the nation in board certified teachers. With a growing trend toward increased standards in education, many experienced teachers are going through the rigorous evaluation to gain professional recognition and possibly more money. Minnesota Public radio's Tim Pugmire reports... The National Board for Professional Teaching Standards began in 1987 as a way to increase teacher professionalism, upgrade learning environments and improve teacher training. Educators, government officials and business lead