"In 1894, only a decade after Harvard adopted letter grades, a group of professors began complaining that 'grades A and B are sometimes given too readily' (Goodwin, 2011, p. 80). The concept of grade inflation has been with us ever since. Grade inflation is derived from the belief that rigor equals a scarcity of high grades and that the purpose of grading is to sort and rank (13)."
Rethinking Grading: Meaningful Assessment for Standards-Based Learning, by Cathy Vatterott