I use what seems to me to be a very logical grading system. I grade papers on a letter grade scale and then calculate grades as a weighted average of these letter grades. Say there are three papers weighted 25%, 25% and 50% that got BC, B, and A respectively. The grade would be 2.5*.25 + 3*.25 + 4*.5 = 3.375, a grade I would then interpret as a low AB. Clear, logical, fair.But as far as I can tell, the course software cannot handle this kind of grading. It assumes that everything is percentages or points. So I cannot use it as an online gradebook. And I have had over the years a large fraction of TAs who cannot quite understand the logic of grading papers with (gasp!) grades. I cannot understand their confusion. To me this seems only logical. Ultimately we will give letter grades, why not set the standards for the grades and grade that way from the beginning? But, instead, they set up their own 10-point or 100-point or 24-point schemes for grading papers, and then I have to ask them, well, so how does this translate into grades? And they look at me with puzzled expressions. I don’t get their confusion.
For things like tests or homeworks that are more point-like, I use linear equations to transform the points to the 4-point range and put those into the grade calculations in the same way. This is a little more outre and would not have been possible back in the days of paper gradebooks, but after all, you have to take algebra BEFORE you get to college, and we have had computers with spreadsheet programs readily available on college campuses now since the mid-1980s.
So I ask you, why do my university and most of my colleagues and students still assume that everything will be calculated on a percentage basis and then curved to grades? For that matter, why are most of you just blindly assuming that everything should be done in percentages even though virtually every school in the US reports grades on a 4-point letter grade scale? There are a lot of reasons why the percentage-point system has problematic properties, but even if you have a good reason to like it, is it really that hard to understand why I’d like my system, or understand why I prefer it? Is it really that crazy to expect that to be an option in campus course software?