One problem that teachers end up thinking about a lot is how much homework to assign and whether to include it in the final evaluations of student performance. In this blog post, I’ll address only the first question—how much to assign, not how to use it.
For college students, there is a fairly simple rule to follow: being a student is a full-time job. For example, on my campus, the standard full-time load is 15 units. If we assume that a full-time job is 40–45 hours a week of work, then each unit should translate to 2.7–3 hours of work a week. That work includes attending class (and labs), doing assigned reading, doing term papers, and doing homework. Our classes are typically 5-unit classes, with 3.5 hours of lecture a week, leaving 9.8–11.5 hours a week for reading, homework, programming assignments, and term papers.
Although this guideline is simple, guessing how much time students take to do the assignments is often difficult. For example, a simple programming assignment might take the top students in the class only a couple of hours to do an excellent job on, while the bottom students in the class may spend 10–20 hours to get an only partially-functioning program written. Reading is also highly variable, with college reading speeds seeming to range from about 30 words per minute to 600 words per minute—and some students never bother to do the reading at all. The workload of the course should not be based on the least competent person in the class, who may not be prepared to do the work no matter how much it is watered down, nor should it be based on the top student in class, as tempting as it is to think “well, G— can do it, so it can’t be asking too much”.
The best approach I’ve found is to do the assignments myself, and assume that the students will take about 3 times as long as I do for each assignment. Getting feedback from the students on how long specific assignments took, and how much time they spent total on the course can also be useful for adjusting the workload to a reasonable level. For courses with a larger difference in expected ability between teacher and student, a larger ratio may need to be assumed.
Many middle schools and high schools set up their homework expectations based on “preparing students for college”. One common rule of thumb one hears is that the total homework load should be 10 minutes per grade level per night (so 10 minutes a night for 1st graders and 2 hours a night for high-school seniors, counting 5 nights a week). Let’s compare that with the college expectation of 40–45 hours a week of work, including classes. My son’s middle school had the students for 34 hours a week. That includes lunch, but many students did homework or met with teachers during lunch, and there wasn’t time for them to go elsewhere, so we’ll count that time as part of their work time (if you insist to treating this a free time, reduce the schooling time to 30 hours a week). A full-time load for the students would thus involve 6–10 hours a week of homework, which comes pretty close to the 80 minutes/night * 5 nights = 6.67 hours/week. The high school my son is attending next year generally has the students for 27.5 hours a week, so a full-time load would mean 12.5 hours of homework a week, or 150 minutes of homework a night. Of course, many students at that high school are taking 8 courses a year instead of 6, so if we figure a 45-hour week for them, we get 36.25 hours of school and 8.75 hours of homework for 105 minutes a night (pretty close to the 90–120 minutes a week of the rule of thumb). First through third grades at one of hte local elementary schools has 28.25 hours of school a week, so with the rule-of-thumb homework load, the kids have 29-hour to 30.75-hour work weeks—about a 3/4 time job rather than a full-time job, but certainly enough for 6–9-year-old kids.