In 2021, the 100-point grading scale is still the primary grading system used by most schools, colleges, and universities. Yet, for over a century, it has been known that this 100-point grading scale suffers from extreme statistical problems that render the results essentially useless. But we continue to use it! In fact, it has become so ingrained that change seems unlikely in any realistic way.
The problem is that an assessment can be statistically analyzed (ie, graded) in many different ways, depending on the teacher. One teacher may give a student a 50; another may give a 90. Over time, this variance builds up so that the final grade a student has is simply a culmination of rampant subjectivity. This also helps explain racial biases present in many school systems across the country.
The problem, when it really comes down to it, is that the rating scale – 0 to 100 – is so large that it makes any specific assignment largely meaningless. What’s the difference between a 70 and a 71? Nothing? Well why HAVE the difference if it means nothing? Additionally, in most systems, failures occur over 60% or more of the entire rating scale: If a 20 and a 60 are both failing and both convey the same deep gravity of a student’s ineptitude at the topic, why is it necessary to separate the grades by 40 points?
The entire system is “simple” and “intuitive” because it bases everything as a percentage out of 100, but this presents more measurement and statistical problems than solutions! As “intuitive” as it may be, it is definitely NOT a valid instrument of measurement in most cases, I argue.
But alas, I doubt the situation will meaningfully change in the coming years. Without a real push to a rating scale that makes sense (such as a simple 1-4 rating) or an assessment system that bypasses grading altogether (for example, see mastery.org), I wonder how many more millions of students will have their academic trajectories damaged or destroyed beyond repair at the whims of the 100-point system. I personally believe most students are creative and educationally astute, until we stomp it out of them.
I am running a grading experiment, if you will. Go to https://forms.gle/TQhdfy851784Y1x69 to play along – it’ll take 2-3 minutes to grade a short mock test of a 3rd grader. My aim is to illustrate, empirically, how wildly grades can vary, given the whims and fancies of the grader. Maybe, one day, this issue will get the attention it deserves. Until then, here’s an A+ for sticking with me. Meaningless? Yes, why, yes, it is…