Friday, November 1, 2013

Mastery-based grading

At NewAPPS, Mark Lance makes a sensible point about one of the oddities of how grading is typically done at the college and university level: Students' grades are usually calculated based on the work they do across a course instead of based on the level of ability or mastery they've achieved by the end of it. This has the somewhat perverse implication that two students could end up with very different grades despite the facts that (a) each of them manifests the same level of ability or mastery by the end of the course, and (b) one of the students has, arguably, accomplished more in the course in terms of learning:
Consider the typical way we grade students in a course. We give a number of assignments. We grade each. Then we average those grades to get a course grade. That course grade is then taken by various outside agents - employers, grad schools, etc. - to be a measure of accomplishment. But there is one very obvious irrationality in this system. Consider two students: student 1 has had the benefit of excellent prior training at, say, a top private HS.  2 has gone to much weaker schools. Maybe 1 has already had some philosophy and certainly has good training in writing papers. 2 does not. Thus, on the first assignment, 1 ends up with a much better grade than 2 because the paper is just plain better. Over the course of the term, however, 2 improves at a vastly higher rate and by the end of the term they are doing work at the same level. Even those professors who include "improvement" as a factor in the final grade are likely to give 1 a higher grade than 2.  (Let's assume that 1 does better on all assignments up to the final one, but stipulate that one's assessment at the end of the course is that they are now producing work of equal quality.) ... that will have unjust effects on their future. I mean "unjust" in the most straightforwardly meritocratic sense. Even if we ignore all other factors, the uptake of a B for one student and an A for another is that the latter is "better" at the course material, or at least did better in the course. But that is just false if they both end up with equal competence and understanding at the end.

I think Mark is on to something here: I've often favored mastery-based grading (what can the student do) over task-based grading (what did the student do). For one, it focuses students' attention at the right things. Too often students approach their coursework largely in terms of getting good grades on particular assignments and tests rather than on mastering the knowledge or skills involved. Of course, if we design the assignments and tasks well, we'll be measuring student knowledge or skill. Still, task-based grading seems to encourage students to take a very short-term perspective on their work. Second, mastery-based grading is more 'real world.' In non-academic settings, people will expect you to be able to design that building, produce that sales plan, perform that surgery. You don't 'get credit' from your employer for performing tasks at less than a mastery level. 

The challenge is this: How could we introduce master-based grading into philosophy classes? (In the comments at NewAPPS, Dustin Locke describes a possible way to do so.) And I would expect many students, accustomed to the task-based approach, will rebel. Has anyone out there tried to grade more based on mastery than discrete task performance, and if so, how?


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  2. The idea is good in principle, but I worry about it in practice, for a reason that is stated by a few commenters at NewAPPS: if grades rest entirely on what the student does on the last assignment and/or the last exam, then many students will not be motivated to put in their best effort on earlier assignments -- which will greatly limit their learning and thus their ability to do well on those crucial final assessments. In an ideal world the students would realize this, of course, but.... Particularly at an institution like mine, where many students lack a strong internal motivation to work hard in their classes, I think a full version of the mastery approach could be disastrous.

    That said, I implement a weak version of the approach in most of my classes, by heavily back-loading the assessment weighting. For example, when I teach PHIL 101 almost half the grade is determined by the final exam and final paper.

    I'm sometimes tempted to strengthen the mastery aspect of my classes a little bit by stating that, if a student's performance on those final assessments is better than their performance on earlier assessments, then I will determine their grade based solely on the former. Indeed I actually do this in my Logic class: if their score on the final exam, which is ordinarily worth 50% of their grade, is better than their combined score on the previous parts of the assessment, their grade is then based on the final alone. But I combine this with a strict regimen of homework assignments all through the class, which they must complete regularly. If they skip too many homework assignments, they start to incur extremely severe penalties, which pretty quickly make an F inevitable if they persist in skipping the homework.

    I haven't done this in my other classes. I do like what Dustin Locke is doing, though. I may try out something like that in my classes next year.

  3. Ann Cahill and Stephen Bloch-Scuhlman had an excellent piece on this sort of approach to a Critical Thinking course in Teaching Philosophy last year:

    They use the same martial-arts analogy. With sequentially ordered skills like argument mapping, Critical Thinking can work in a similar way. Students have to show that they have mastered each skill (e.g., distinguishing premises from conclusions) before moving on to the next (e.g., simple argument mapping). I've employed this in my courses with some success.


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