How do you decide whether to grade an assignment using a letter grade scale (A, B, C, etc) or a numerical scale (percentage, points, etc)?
First, decide what the learning goals are for your assignment. Mastery of content, knowledge of specific concepts, articulation of degree of understanding? It’s a good idea to have some specific criteria in mind before you hand out the assignment, and to share those criteria with the students in your class. Here’s a great website about developing grading criteria: http://cft.vanderbilt.edu/teaching-guides/assessment/grading-student-work/
Exams and quizzes lend themselves to numerical scales. These kinds of assignments ask often for particular content, for understanding of particular concepts, for demonstrated ability to use material or apply material.
Many papers, though, tend to be best graded on a letter scale. Why do we tend to think this?
A letter-based scale seems more qualitative. Here’s a letter-based set of criteria that I’ve employed:
- A indicates achievement of distinction. It involves conspicuous excellence in several aspects of the work. The paper is well-written, persuasive, and engages my attention. Interesting examples and specific, appropriate evidence are included to support the writer’s position. The work is organized, thought-through and clearly was revised and edited for flow, accuracy and style. Generally these papers are a pleasure to read. An A- paper might have some errors, grammatical or of omission, but is basically well-conceived.
- B indicates general achievement of a high order. It also involves excellence in some aspects of the work, such as completeness and accuracy of knowledge, sustained and effective use of knowledge and supporting evidence. The paper is organized, but the style of the paper is not as elegant. The presentation is clear, but not thorough or might have paragraphs that are less well put together. These papers would benefit from some revision and editing. These papers are usually pretty boring to read and take me a long time to wade through.
- C papers do address the assignment and contain some supporting evidence but it’s not provided in a way that strengthens the paper’s positiion. It is clear that the student is familiar with the topic assigned and has made an effort to convey understanding. But, the paper is not well-organized, the word choice is not elegant or sometimes has inaccuracies. Often these papers are more opinion-pieces without adequate support. The writing is broad and not interesting. Sentences like, “The work by those scientists was really interesting and it had a big effect on the field.” The paper has errors and is in obvious need of revision. These papers are often quite hard to read and tend to put me to sleep.
- C–, D+, and D indicate degrees of unsatisfactory work. There are usually many inaccuracies, little or no supporting evidence. These papers, rare for me to encounter, are brutally painful to read. I hardly ever encounter a paper that would earn a grade in this range.
I can’t even mention F. Usually I assign an F grade to work that is turned in so late that it’s acquired substantial late penalties. I suppose if the paper had nothing to do with the assignment, it could receive an F.
This kind of written work puts forth the quality of mind, the quality of the student’s understanding and ability to express that understanding clearly and cogently.
Another kind of grading scale, often used for multiple small assignments like one or two page “response” papers on assigned readings or problem sets might be graded on a “check”, “check-minus,” “check-plus” scale, or on a 10-point scale. The most important aspect of these papers, in my mind, is the commentary I write at the end of the paper, to help guide students in their thinking as they do subsequent writing assignments for the class. Over the course of the semester, if the student attends to these comments and tries to work on the presentation of thoughts and ideas, these smaller assignments will get better and better and this will ultimately lead to better grades on larger paper assignments.