In England, every year, more than a million high school students take GCSE (age 16), AS (age 17) and A level (age 18) exams. The grades those students are awarded are important. Good grades open doors. Poor grades slam them shut. So it's vital that those grades are reliable, and can be trusted. The truth, however, is that about 1 grade in every 4 is wrong. Without any right of appeal. That means that of the approximately 6 million grades awarded each summer, about 1.5 million