Study critiques schools over subjective grading

Washington Post:

If you have ever rolled your eyes when your child says a teacher’s grade was unfair, you might want to think again. Your child might be right.
Douglas Reeves, an expert on grading systems, conducted an experiment with more than 10,000 educators that he says proves just how subjective grades can be.
Reeves asked teachers and administrators in the United States, Australia, Canada and South America to determine a final semester grade for a student who received the following grades for assignments, in this order:
C, C, MA (Missing Assignment), D, C, B, MA, MA, B, A.
The educators gave the student final semester grades from A to F, Reeves said.
Why? Because, he said, teachers use different criteria for grading.