XP and Grades: Moving from Subtractive to Additive Grading

In my gamification journey, I’ve learned a lot through trial-and-error. In this blog series, I’m going to outline how I developed my gamified grading system to increase student engagement and focus on learning. To begin, I’ll look at why I changed the way I grade and some initial setup.

Traditional grading is a top-down system that creates more stress on students. Their grade begins at 100, and then grades average out from there. In this system, students have nowhere to go but down, and whenever the grade drops, they need extra points to bring it back up. How many times have you had a student do bad on a quiz and immediately ask for extra credit? That’s not learning.

Subtractive grading reminds me of the 100-second challenge I saw at the Renaissance Festival. The goal is to hang from a pull-up bar for 100 seconds. Anyone that can do that wins $100. It sounds simple, but the same thing happens to most people. Things start out great, but eventually gravity starts to take its toll. You can see their muscles start to ache. They start squirming around. Eventually, the stress of something seemingly so simple as holding your own body weight becomes too much, and they let go. Trying to maintain a good grade caused this same kind of reaction in my students.

Instead, additive grading starts everyone at zero and builds from there. As students complete tasks, master content, and engage in class, they earn points that adds to their total. Everything they do helps their grade. The only thing that hurts their grade is stagnation.

It makes sense when you think about it. Why should someone start with 100% in a course they just started? We’re used to starting at zero in everything else in life. No video game starts with the character at max level (unless they lose it all in the prologue). No progress bar for any course gives you 100% completion when you start it. We don’t go into jobs starting with the maximum salary. You don’t just jump straight into the championship game. In all those scenarios, and more, we start at the bottom and work our way to the top. So why are grades different?


So let’s talks practical. How do we actually do this in our classrooms? After spending a couple of years reading and studying and tweaking my own grading, I’ve put together a pretty easy way to do this. Essentially, it comes down to levels, experience points, and grade equivalence.


The easiest place to start is with levels. Originally, I capped the levels at 60. It felt more game-oriented, but it was a little difficult to work with, so I’m changing the level cap at 100. For one, it makes it easy to determine grade equivalence. Also, this many levels allows students to earn multiple levels a week, which helps students see that they are making progress.

Grade Equivalence

After determining the number of levels, you’ll set up the grade equivalent for each level. This is one of the main reasons I’ve moved to a 100 level system. The grade is already there. Whatever level they end up with at the end of the grading period is their grade. If you’re using different levels, you’ll just need to the grades for each level.

When I was using 60 as the max level, I had to do some math and multiply 60 by each percentage grade (.99, .98, .97, and so on). I didn’t have every percentage grade, so it looked like this:

It was tougher to work with, so I went with 100 levels instead.


Determine XP

Finally, we’re ready to determine how much XP students need per level. If you want, you can have a standard XP per level to give it consistency. You may have students level for every 1,000 XP they gain.

I decided to go with some gaming level formulas for mine. This give it more of a gaming feel for me. You can look up various formulas that different gaming systems used, but I settled on this one: 250*(x1.25).

Here’s what mine ended up looking like:


I used Google Sheets to calculate all of the XP values per level. If you’re using a leveling formula and want to learn how to do this quickly, check out my tutorial here.

Whatever you decide on XP, though, is arbitrary because you’ll be tailoring weekly XP values based on your totals, which I’ll discuss in the next post.

Published by mltucker83

I am husband, father, educator, writer, preacher combined into one easily-sunburned man.

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