Current notions abut assigning grades take on a different aspect when viewed through the lens of PBL.
For instance, consider the idea that giving daily grades is a good thing--isn't it? If students have to prove their knowledge often, I'll know exactly what they know, right? And if I've given lots of graded assignments, then one or two missing assignments won't cause them to fail. That's fair, right?
Not so. Giving lots of graded assignments creates more work--for both the teacher and the student. Instead of spending time pondering how best to engage students in their learning, reflecting on why a certain concept is so hard to teach, searching for ways to increase collaborative accountability, or a multitude of other worthy endeavors, teachers spend hours and hours looking at student work--much of which does not meet minimum expectations--and entering grades that only reflect the minutiae of what students are supposed to learn. Instead of digging into content and creating solutions to complex problems, students spend time looking for papers in their backpacks, scribbling incomplete and shallow responses to questions, or guessing what to put in the blank to avoid zeroes in the grade book. Imagine if assignments were fewer, deeper, more engaging, more relevant. Imagine if students were taught how to give precise, considerate critique to each other along the way, so that by the time the teacher views the work, it is as exceptional as the student can possibly make it. Win, win. Students feels successful. Teacher feels successful. But that can't happen if there is a graded assignment every day. There simply isn't time.
Daily grades are also no guarantee that students are actually competent in the subject matter. A daily grade is an opportunity for a student to replicate how to solve an equation or write a complete sentence. But regurgitation is not knowing. A daily grade might be an indicator that at that particular moment, the student hasn't mastered a skill. But it's not a reflection of what that student might be able to do with support. Besides, poor daily grades are discouraging. For students who struggle, poor daily grades can be a reason to stop caring. Instead of daily grades, imagine if teachers presented intriguing problems that could be solved through the real work of the discipline. Imagine if that same teacher provided students with rubrics that represented the evolution of how their thinking and comprehension would change as they explored a subject deeply in order to solve that intriguing problem. Imagine if students were taught to use these rubrics to evaluate their own learning, and to share their progress with their teachers. Would you even need daily grades?
Giving an abundance of graded assignments to ensure students pass their classes dilutes the meaning of every assignment. Grades are supposed to reflect what students know, not their ability to hit the submit button or turn in an essay. Does it really take 30 grades to prove their knowledge? After guiding students through rigorous problem-solving methodologies, deep discussions, peer critiques, and sturdy self-evaluations, teachers would know exactly what their students know and don't know.