A Lesson in Rubrics

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I grade for a graduate level course in Machine Leasrning. As most people who teach in universities, I have never had any formal training. All my training has come from person experience, what I have been able to pull out of other teachers (themselves not being trained), and research. With this base, the following is a recreation of the “rubric” that I was able to come up with for the assignment:

criteriapointsearnedcomments
Grammar4  
Structure4  
Hypothesis5  
Experimental Design20  
Conclusion/Analysis20  

Later editions of this rubric would breakdown blocks into smaller components to try to help explain what goes into each:

  • Experimental Design: ## / 20
    • Methods: ## / 5
    • Validity: ## / 5
    • CV: ## / 2
    • All datasets: ## / 4
    • Communication: ## / 4

As you might expect, this did little to effectively teach the students what what missing and how to improve. If you are familiar with rubrics at all, you should easily point out that this is not a rubric in the slightest. It is indeed a weighted checklist. One of the biggest weaknesses of this style is that an explanation of the points deducted has to be explained from comments left in the assignment/on the rubric or through direct conversations with students. This means that the students are not effectively getting the information that they need, especially if they don’t reach out about deducted points, and I have to spend a lot of time commenting PDFs or typing out emails. There has got to be a better way to do this! (Hint: anyone who knows anything about grading/teaching knows that there are rubrics)

So, on to writing rubrics I went. If you don’t know how a rubric should look, it is typically in the form of:

criteria4321
Some criteriaWhat defines a 4/4 on this sectionA little less than 4/4, but better than a 2/4What defines 2/4What defines a 1/4

Some rubrics have 3 tiers, some have 5. What if you don’t want to grade on a discrete scale? Allow decimals to be used and sort them into the larger of the two boxes. Student’s can read this as a weighted average of the two blocks (a 3.4 will have 40% of the 4 and 60% of the 3). What if you don’t want to limit the scores of the criteria to such low values? Using the numbers as a fraction of the total score instead. So, 3/4 will be 75% of the total possible points. So, if you will to let Experimental Design to have 20 points, and the student achieves a 3/4, then they would get (20 * 3/4 = 15) points. My course uses Canvas, and Canvas’s rubric functionality allows you to automatically scale values by changing the “out of” score.

So, what are the benefits? TODO: Add research that defends the use of rubrics.