Piloting a Subtractive Grading Scheme in Engineering

Many grading schemes in post-secondary engineering education utilize an additive grading scheme, where each student starts with a grade of 0% and slowly builds up towards 100%. This study looks to examine the opposite, using a so-called subtractive method wherein each student would start at a grade of 100% and then, for each assessment, would aim to maintain that grade. Nineteen (19) students participated in the study across three courses, with 15 and 4 students in the subtractive and additive schemes, respectively. Survey data showed that students feel that the subtractive grading scheme is fair, and there has been no observed statistically significant difference in the overall performance of students in the additive vs. subtractive grading schemes. This pilot study has shown that the student perspective on differing grading schemes are similar and that these schemes could be broadly implemented as an option for students when enrolling in a course.