An effective education system is one in which the average student performance is high using well-established national and international standards. Additionally, the system continually makes significant progress in improving student performance. System-level measures of effectiveness include graduation rates and student performance on standardized tests. Two of the most commonly used tests are the National Assessment of Educational Progress (NAEP) and the Program for International Student Assessment (PISA). Both meet the highest standards of reliability, validity, and social relevance. NAEP measures what American students know in math, reading, science, writing, the arts, civics, economics, geography, and U.S. history. PISA measures student performance across nations in science, mathematics, reading, collaborative problem solving, and financial literacy. These measures indicate the U.S. system is failing in terms of student performance and a lack of improvement over time. While the graduation rate has improved to 82% over the past 6 years, almost one fifth of all students fail to complete high school. As of 2015, only 37% of 12th-grade students were proficient in reading, 25% in math, and 22% in science. The United States ranked 25th among other nations in science, 22nd in reading, and 38th in mathematics.