When I taught 11th grade, I taught several classes where a good handful of students did not regularly turn in homework. Many of them completed all of the work late and turned it in for half-credit, which for many of them was enough to boost their grade just above failing. The first batch of quiz grades revealed that this strategy was a bad idea, but it was hard to convince students of that fact. I decided to use math to prove my assertion that turning in homework on time is a good idea.
I did this by making a table (with no identifying info other than what class a student was in) of how many assignments a student completed on time, and what their quiz grade was. I graphed the resulting charts and showed them to all the classes. Here is an example of one of those charts:
Some students needed an explanation of what the graph means. If you have students in the class at a high enough level of math to explain it, have them help you. If not, pull out a couple examples (e.g. “Look at this student who turned in 9/9 homework assignments on time. What grade did they get on the test?) and explain that the graph is sloping up, meaning that the more homework assignments a student turned in on time, on average their test scores were better. Of course there are exceptions, but are most people an exception? No.
Positives: For some students seeing proof of the trend will help convince them to make different choices.
Negatives: Did this convince everyone to change their wayward homework habits? No. At least hopefully now when they