The Zero Has Got To Go (at least how it is currently employed)

I don't know how long I have been working with a base 50 in my class, I think this is the 6th year, but I can tell you why I started. At a school I was teaching I had a student who messed around and goofed off for a good chunk of the first semester, but he's a 7th grader and they make these kind of crazy choices. He came to me and for some strange reason, for which I am still not privy, he was wanting to turn things around. At this point the student had a 12 or 14% in my class and There was no way that even with him busting his tail the rest of the semester was he going to dig out of that hole. When he realized this, he just quit working. That bugged the crap out of me. I wanted to help but I also wasn't about to just falsify grades to get him back to where he could dig out but I didn't have another way. I started to research on the web and stumbled across the no zeroes/base 50 idea in an article. I started thinking that the same student would have still been failing but he would not have been in a hole so deep he couldn't dig out had I had this system in place. Now, not the best reason to switch but it was the reason I originally switched. I didn't have a clue that this was even an option seeing as I never had a teacher that worked that way. As I researched more I became more and more convinced that the zero wasn't the problem but the 100 point scale. It didn't make mathematical sense to me that the F part of the scale so greatly outweighed the rest of the scale, and since I couldn't get rid of the 100 point scale (digital gradebooks) I felt like the next best thing was to shrink my grading up to even all the grades to 10%. Let's take a look mathematically at how a 0 affects the grade (assuming you still love or are stuck to the average score like am). Let's say that you are trucking along getting B's, let's say you are getting 85's and you forget your homework one day (ugh, I'll take about how I feel about grading homework later) and for that assignment you get a 0. Let's say that up until that point you have 10 grades, 85x10=850 and then you get that 11th grade that is a zero. So now that 850 points are now going to be divided by 11 grades to give you a 77% as your average. So with 10 grades at 85% and one at 0% you have now gone from having a B to having a C, an 8% drop from 1 grade that is weighted the same. Does that C reflect the level of work you have been doing in the class? NO! You have been getting 85% on everything, you should have an 85%. With a base 50 that student, even with averaging, still ends up with an 82% (900 points/11 grades) All of this stops mattering if we don't have to use the average, which many of us are stuck to in one way or the other. If I could find some way around the aggregated score and work with something like the mode instead, the fact that the student had one zero wouldn't even matter because the mode would easily be found to be an 85%. Not only that but for this to matter even less, I wouldn't allow that zero to stand there in the gradebook because if it was so important that it had to be factored into the representation of student learning we call a grade, then I would have them doing it and completing it at some point, but that's for another post.

Rick Wormeli spells this whole thing out pretty good in this video.