You may have seen the headline, “Teacher Fired for Giving Students Zeros for not Turning in Assignments”. Certainly great click-bait from a publisher’s standpoint, but what is this really about.

At a conference roundtable I attended many years ago, we discussed this very topic. The premise that, if you grade on a percentage basis, giving students zeros for assignments not submitted is disproportionately punitive, discourages improvement, and sets up at-risk student for failure. The old school argues that in the “real world” we only are paid when we show up, and a system that awards a grade, other than zero, for no submission does nothing to encourage student work and is unfair to the students that do the work. Proponents for change advocate giving a grade closer to 50%. Their argument being that it provides a more just grading system and better reflects of the student’s academic accomplishments.

Without getting too deep into weeds of the psychology of grading systems, let us look at the pure mathematics of the two systems by exploring some examples and the effects of both grading systems on a couple of students, one strong and one weak.

In Example 1, Suzy is clearly a strong student. Her average of 90% is representative of her academics, and the objectives met in the course. In Example 2, Suzy is again the same strong student, but who has now missed an assignment for one reason or another and her average of 72% may not seem as representative of the same academic effort. In Example 3, Suzy has received a 50% for the missed grade. Arguably, the 50% still negatively affects her grade, but the average grade may seem more representative of her academics.

Jane, a weak student, receiving a zero for a missed assignment sets up a scenario such that it is almost impossible to pull up her grade without scoring significantly beyond her normal academic abilities. Couple this with the fact that the zero, earned in the first assignment, generates respective averages over the next four assignments that most students would find disheartening; 37.5%, 46.7%, 55%. On the other hand, a grade of 50% for the missed assignment creates a situation where she may yet still succeed.

For comparison, consider assigning a zero on a 4.0 scale. In the table below, I have assigned grades that are roughly equivalent to Suzy’s example. It is clear that earning a zero on a 4.0 scale is not nearly as punitive as a zero on a percentage scale.

Some would argue that this is a good reason to drop the lowest score, or scores, in a semester and I would agree that it does indeed mitigate the issue to some extent. But given the mathematics of assigning a zero for a missed assignment, at the very least, it does invite a closer examination of how we as instructors design our grading systems.

Below is a link to an article written for the National School Boards Association discussing this topic.
https://www.nsba.org/newsroom/american-school-board-journal/latest-edition/less-zero