There are a million debates about how or whether we should grade, and many people smarter than me have spent thousands of words explaining and advocating and rhetoricizing for all kinds of philosophies and systems. No matter what system you use — standards-based, traditional, 3P, no grades at all — I'll just put out a few things that I think are true about grades in general. 
1. The point is long-term flourishing.
Long-term flourishing isn't the A of the ABCs of teaching and education — it's the whole alphabet. Whether we're contemplating grading or instruction or curriculum or after-school clubs, keeping our eye on that Everest of Everests will save us a lot of grief.
So, when we consider our grading practices, the question is: “How does this affect the odds that my students will flourish long-term?” Sometimes, the answer is, “Not at all” — and in these cases we need to move on quickly to things of greater import. Other times, the answer is, “Hugely” — that's when we dig in and do some further thinking, researching, and discussing.
For the limited time that I possess as a teacher, husband, and father, I've yet to dig deeply into the comparative merits of this grading system or that one because I'm still working to ensure that I'm as good as I can be at providing curriculum and instruction that aligns with the Non-Freaked Out Framework. My hunch is that this will have a greater long-term impact than whether I make assessments worth 60% or 65%, or even more time-consuming, align the whole gradebook to a set of standards.
Now, if my district were to announce tomorrow that we're switching over to standards-based grading, I would move in that direction at the general speed of the district, satisficing it for the sake of saving my best work for helping students become better readers, writers, speakers, thinkers, and people.
2. No silver bullets.
Every system I have seen people advocate for has its issues — anyone who tells you otherwise is either selling something or drinking the Kool-Aid. No matter what system you use, there are going to be benefits, and there are going to be problems. For example, traditional grading produces a percentage from 0 to 100 that's a mixture of behavior (e.g., I didn't turn the assignment in, so I got a zero) and performance (e.g., I scored an 8 out of 10 on the retrieval practice quiz), and tends to vary wildly by teacher, course, and/or department. Strangely enough, this somewhat chaotic stew produces a fairly strong predictor of positive life outcomes: GPA. (More on that in #4.) So, problems and benefits.
Anyone telling you that one grading system is bad for all kids is overstating their case. Public education is still an experiment — and not all that old of an experiment by world historical standards. As such, grading, too, is largely experimental. No matter what, you're dealing with the complex task of assessing humans on their learning — let me know when you dial that in to something perfect and (importantly) manageable by us mere mortal teachers 🙂
With #1 and #2 taken to heart, we can start to dig in to the work of making our grading as good as it can be.
3. All systems must be wrestled into something that is doable for teachers and understandable to students and parents.
If the perfect grading system requires teachers to spend unsustainable chunks of their time assessing or inputting or Managing the Machine, then it's not a perfect system. Every minute spent grading is a minute that can't be spent planning, researching, tutoring, or living a full and balanced life. Our careers come down to the way we use minutes, not the way we use years.
The best grading systems will also be student- and parent-friendly. For my students who are academically novice, this means I have to spend some time teaching them how grading in my class works. They have to understand the ratios and percentages and the basic mathy stuff (e.g., tests and essays are worth 60% of your grade, while homework and classwork are worth 20%), and then they need to evaluate how this might affect their strategic approach to the coursework.
Parents, too, need to understand the system. The better I am at communicating how grading works in my course — through the syllabus, through conferences, through the occasional email newsletter — the better the chances that parents will do their part to support their child in succeeding and lower the chances for grades-related fireworks at parent-teacher conferences.
(For three tips on working better with parents, read this post.)
4. On a course-by-course basis, grades don't seem to matter a ton. Taken together as GPA, they do seem to matter.
This one is less of a “belief” and more “something I've been learning recently.” As I said in “Are We Measuring the Wrong Things?”, even for all of the idiosyncrasies that come together to form a student's GPA — this teacher allows study guides, that one does test corrections, another is notoriously stingy with A's — GPA is somewhat predictive of positive life outcomes.
The following points are from research cited on pages 3 and 4 of Teaching Adolescents to Become Learners (access it here for free; see Figure 1):
- GPA is predictive of future outcomes, much more so than standardized test scores.
- GPA in the middle grades (and even earlier) is predictive of high school success.
- High school grades are stronger and more consistent predictors of college persistence and graduation than college entrance examination scores.
- One study found that high school grades were stronger predictors of both college GPA and college graduation than students' SAT scores, class rank, and family background.
- Grades go beyond measuring content mastery; they also reveal qualities of motivation and perseverance, as well as the presence of good study habits and time management skills.
- High school grades have been found to have strong, significant relationships with earnings nine years after high school, for both men and women, even after controlling for educational attainment.
- Links between students' class rank (as determined by grades) and length of life, possibly because good grades reflect having established responsible patterns of behavior during adolescence.
- There are still things we don't know about GPA. For example, more research is needed to determine why GPA predicts future outcomes. The “prevailing interpretation” is that grades reflect both cognitive and noncognitive factors, with those noncognitive factors including behaviors, attitudes, strategies such as “study skills, attendance, work habits, time management, help-seeking behaviors, metacognitive strategies, and social and academic problem-solving skills” that help people succeed in new environments and dominate “new academic and social demands.”
(I discuss the noncognitive factors further in The Student Motivation Starter Kit.)
As you can see, I've certainly not “arrived” when it comes to grading systems — there's still much to learn, and I am thankful that many people are pouring research into figuring this out. In the meantime, the above beliefs help me breathe a bit easier while I continue digging into the work of helping my students improve as readers, writers, speakers, thinkers, and people.
- For whatever it's worth, my school uses a traditional system, and I don't rock the boat on it.