Over the past several years, the Science Department has been adjusting their grading systems. Deviating from a traditional “percentage-based” grading system, many courses have increasingly begun to adopt “mastery-based” grading scales.
A mastery-based grading system aims to assess a student’s understanding of course material by assessing one’s performance on individual problems and concepts as opposed to a total percentage on a test. The Chemistry Department, for instance, tests using four, five, and six-level problems that correspond to different levels of difficulty. In courses that adopted a mastery-based grading system, there have been zero to minimal changes to final grade distributions, as stated by Keith Robinson, Chair of the Biology Department and Instructor in Biology and Chemistry.
According to Andy Wall, Science Division Head, Chair of the Chemistry Department, and Instructor in Chemistry, the current department-wide mastery-based grading system began development eight years ago. Since then, it has undergone many revisions. Wall detailed the objectives and benefits of implementing the new system.
“A key issue that we were seeking to address by developing this new system was the shifting of student mindsets away from numbers to focus more on learning. In the past, after handing back tests we’d have lines of students arguing for points, or even fractions of points, because they were trapped in the game of percentages… Now we can have conversations with students about how to develop their fundamental skills to answer questions with increasing complexity or about how to approach solving problems that they have never seen before,” wrote Wall in an email to The Phillipian.
He continued, “Another major benefit is that we don’t penalize students for trying the hardest questions… In the new grading system, students know clearly what is expected to earn a 4 or a 5, and if they get the 6-level questions wrong, it doesn’t take away from the good work they did to earn that 4 or 5. There is no harm in trying the 6-level problems.”
Last year, the Biology Department began rolling out a “learning-target” based system in Biology-500 as part of a gradual reworking of the course, according to Robinson. This system breaks course content into smaller chunks, called learning targets, which are individually graded on a six-point scale. A student’s cumulative grade is then determined by taking each learning target into account. The system offers students test retakes. Robinson noted that the adoption of the “learning-target” system in Biology-100 and 300 is tentative.
“Our purpose was to try to make it really clear to students when we gave feedback in the form of a grade, what were the things that you were doing really well and what are the areas where you’re not quite there yet,” said Robinson.
Having taken both Biology-100 and Biology-580, Cindy Yang ’26 shared her opinion on its grading system, recognizing its importance in developing critical thinking skills. They expressed their satisfaction for the current science grading systems.
“What these systems have made me think about is that you really have to be super thorough in your answers, which I think is actually a pretty good thing. In Bio, whenever there’s short or long answer questions, I really just tend to write a lot and be very explicit about the connections I’m making, how I’m reaching these conclusions. It’s a pretty good thing because it’s teaching us this analysis,” said Yang.
This year, the Physics-100 course adopted a modified version of the Chemistry Department’s mastery-based grading system. John Rogers, Instructor of Physics and Chair of the Physics department, mentioned that the department is open to adopting the mastery-based grading system more widely.
“That’s a decision the department’s going to have to make, and I think we need more data and more information about how it’s working in Physics-100 [before] we expand it to Physics-300, 400, 551 or not. For single section courses, if you’re teaching your own course, as a teacher you can adopt it if you want. As a Chair, I’m fine with anyone adopting it as long as they let me know they’re doing it and we have a plan for it. But for the multi-section courses, we’re going to have to make that decision as a group of teachers, as a department. I’m hoping we’ll try it in more areas because I think it makes a lot of sense, and I think once kids get used to it [they] will like it better,” said Rogers.
Nate Liang ’25, who is currently taking Biology-600, an independent research course, reflected on grading systems in science courses. He underscored the importance of standardizing grading and workload across sections to provide an equitable experience for every student.
“I only really started hearing about grading inconsistencies the year after I took [Chemistry-]550, when I was a Lower… That’s when I figured out that there was some opinion around campus that there might be some grading inconsistencies because my friends were in different classes with different teachers,” said Liang. “Every department should work to [standardize] the work to some degree. I’ll speak for the course that I’m in now. It would be nice if, regardless of whether you take it in the first half or in the second half of the year, that your expectations are the exact same and that the method by which you complete the class is the exact same as well.”
This spring, the Science Division held a department review that invited faculty from other institutions to evaluate Andover’s program. According to Wall, the Science Department plans to use the perspectives offered by the committee and continued conversations within departments to shape future grading systems.
“I believe the most effective grade reform comes from within departments and not from an outside entity. … We’ve seen this in Physics-100, where they have developed their own methods with similar aspects to Chemistry’s grading system. Biology has also been experimenting with mastery grading as well. It’s the combination of innovation at the department level in defining grades, along with conversations across the school, that will lead to the most effective outcomes for improved grading systems,” wrote Wall.
Editor’s Note: Nate Liang ’25 was a Digital Editor for The Phillipian, vol. CXLVII.
