Lagging Homework

This is part of a multifaceted strategy to teach heterogeneous classes.
Read about it in this article: Reaching the Full Range.

One concept which has been extremely popular every time I’ve offered my workshops is “lagging homework”. The idea is to completely separate tonight’s homework from today’s class work. I tend to assign homework about ideas that were introduced about a week ago (more or less.) Here are some arguments in favor of this practice:

  • Students do not rush through classwork in order to “get to” the homework and try to do as much of it as possible in class. As a result, they are more intellectually present, and more available for reflection, discussion, and collaboration.
  • Teachers do not rush through the introduction of a new topic. They are not under as much pressure, because they don’t need to reach all students before the end of the period. If today’s lesson does not go well, there is always tomorrow. 
  • Lagging homework extends students’ exposure to the ideas: what could (with perfect students) be done in one week now takes two weeks, which gives the students who need it more time to absorb the ideas. And this without harming the students who don’t need the extra time. In fact, it gives them an opportunity to later review ideas that they may have absorbed too fast.
  • This policy is also helpful to your stronger students in another way: it allows forward motion to a new topic before every single last student is “ready to move on.” The student who is not quite ready knows that they will have another chance to grapple with the idea in next week’s homework. It is a kind of differentiation that does not require the teacher to come up with a different curriculum for different students.

Exposure can be extended even more by waiting another week before quizzing on that topic, and yet another week before quiz corrections are due. Combining all these techniques can multiply exposure time by four!

But, you ask, are students “confused” by this practice, since it is probably different from what they’ve done before? Yes, but it does not take long for them to buy into this system, for all the reasons given above.

Don’t students need to practice a new idea soon after they hear about it? Well, yes, but that need not be done at home. Giving them a chance to do their first practice in class means that they are doing it in the presence of classmates who can help, and of course a teacher. (This goes along with the “flipped classroom” concept.) In fact, one participant in my workshop told us that once she started lagging homework, the number of students who did the homework increased dramatically. It turned out that part of the reason for the non-completion of homework had been that under the old, non-lagged system, they just didn’t know how to do it.

What are your thoughts about lagging homework? Let me know in the comments.


PS: If you want to read more on this and related topics, see the Teaching page on my Web site, and/or these blog posts:

[More on homework] [More on extending exposure] [Implementation Advice]
[Once again: heterogeneous classes]

5 thoughts on “Lagging Homework”

  1. My AP calculus teacher regularly assigned review after 1 day, 1 week, 1 month, and 4 months. Said research showed we'd remember concepts and procedures better this way.As a student, this nearly killed me! It pushed me to truly understand everything we were learning.As a teacher, I've never had the willpower to organize my homework assignments in this 1-1-1-4 structure.Lagging HW sounds MUCH more manageable!


  2. Yes, it's quite manageable, and does not require the level of organization your AP Calc teacher somehow pulled off! At all times, you're just keeping track of (mainly) two things: new material for class work, and last week's stuff for homework. But it does have the same benefit as his system: extended exposure for better understanding. The one-month review is even part of the system: it occurs if you follow the pattern I suggested in the post for quizzes and quiz corrections. But the four-month review, while a good idea, is not included in the above scheme. To do it requires some other techniques, which I will present in a future post.


  3. Hello..This is the first I have heard of lagging homework, and this year I am starting something similar to the other reply in terms of 1 week and 1 month reviews. I just read your lagging homework and philosophy about quizzes. As far as quizzes based on what I read, were the quizzes were “lagged” also?


  4. I’ve been “lagging homework” for over a decade now… never had a term for it, but all the reasons – yes! Thank you! Yours is the first support I’ve heard for it and I encourage other math teachers to do the same!


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