As I was going through emails in preparation for the 2015 open lab (please let me know if you'd like to attend!), I found this:
I saw in your "Less is More" article that homework [was at that time] 25% of the total grade for your classes. I was considering making homework a much lower percentage but mostly a "good faith effort completion" grade, since I've found it difficult to justify to myself grading students on their knowledge of a material while their still in the process of learning it, rather than an exam where they are reviewing the material. What are your thoughts on this?
That's an important question for any physics teacher to be able to answer. Remember that physics teaching is art, not science -- there are few hard truths of physics teaching, only ideas that work or do not work for each of us. Would pointillism have worked for Picasso? Could Rodgers and Hammerstein have written about singing cats? Maybe, maybe not; yet pointillism and Cats! are indisputably successful things that other artists should at least be aware of. I have my answer to the homework question that indisputably has worked wonders for me and many others. Some good teachers may disagree with me on principle, or may choose not to use my approach in their teaching environment. Yet everyone should acknowledge, whether they use it or not, that my approach does in fact produce considerable success for me and my students.
To the question, then: When you grade homework, you're not grading students on their knowledge of the material; you're grading the skill of problem solving with new concepts, along with students' diligence in seeking the correct answer. Fact is, homework (or any work) is worthless if it's not done carefully with a full effort toward getting the correct answer and approach. "Good faith effort completion" sounds great, but ask yourself -- if you graded students' homework carefully, would they do a better job? Would they perform better on tests?
My answer is, I grade homework carefully and thoroughly on a regular basis, especially early in the year. I grade such that the students expect that their work will be judged, such that the students do their work to the highest standard they can. And therefore, my students don't have to study for tests. And, they perform well on those tests, because they've practiced carefully. The one year when I didn't carefully grade homework, many students did a half-arsed job on the homework, then were upset when their test performance was poor, then complained to all who would listen that physics was too hard and that I was mean and unreasonable in my expectations, that I didn't understand my students.
As for the "fairness' issue, is it fair for the football coach to choose a starting quarterback based on his performance in practice? I mean, practice is when players are supposed to develop their skills, right, and only the game really matters? Yes, but everything's a test, everyone is evaluated all the time. If you grade homework regularly -- even every other night, even only part of one problem, even a grade on a 0-1-2 scale, then you'll have enough data that one bad performance on something a student couldn't grasp quickly will be a mere blip.
I now am counting homework and daily quizzes as half of the student's term grade, with the other half coming from monthly tests. Not surprisingly, there is a very high -- nearly 1.0 -- correlation between homework and test grades. I am virtually certain that the correlation between homework and test performance exists independent of how much you grade, or how much you count the grade. The goal, therefore, is to create an incentive mechanism so that students do everything they can to get homework right. Then test and exam performance will take care of itself.