The OECD initiated the Programme for International Student Assessment, or PISA, about two decades ago, and students in select schools of member and some non-member states take the test every three years. PISA analyzes reading, math, and science skills of 15- and 16-year-old students. OECD released the newest results and although the expenditure per pupil in the OECD has increased by 15 percent in...