The optimal class time for student learning

Last year in B Semester, one of our ECONS101 lectures was scheduled for 5pm. Les and I both thought that class attendance would be really poor for such a late lecture time. It was lower, but not nearly as low as we expected (having incentives to attend class, in the form of extra credit, probably helped). In the A Semester, we have a 9am class, and it seems that attendance for that one is not much greater. Which raises a question: when is the best time to have class, if we want to maximise student learning?

There's at least a couple of aspects to this. First, students may attend at different rates at different times. Early classes may have low attendance if students are late risers, while late classes may have low attendance if students have evening jobs, sports practices, and so on. Second, students might be able to focus and learn better at different times of the day, such as the afternoon, which is why some schools have experimented with starting the school day later. However, university study is different, and students typically have at least some choice over class times (or whether to go to class).

So, it was interesting to read this 2017 article by Timothy Diette (Washington and Lee University) and Manu Raghav (DePauw University), published in the journal Applied Economics (open access). Diette and Raghav used data from "a private highly selective liberal arts college" over the period from 1999/2000 to 2007/08, to investigate whether class times affect student grades. Using data across all year levels, they have over 115,000 observations. They find that, after controlling for student gender, SAT scores (as a measure of ability), class size, level, experience, and instructor and department fixed effects, that grades are lower in the mornings, and higher in the afternoons. The figure below summarises the results from their preferred specification:

All class times before 1pm are associated with lower grades than 1pm classes, and all classes after 1pm (with the exception of 3pm, which is not statistically significantly different) are associated with higher grades than 1pm classes.

Interestingly, when looking at the results for each gender separately, they find that:

Both genders earn lower grades in morning classes and higher grades in afternoon classes... we find that the magnitude of the penalty of 8 am and 9 am classes relative to 1 pm classes for male students is almost double the estimated effect on female students. In addition, male students have a larger benefit from late afternoon classes relative to female students.

The results are not strictly causal estimates, although in their sample, students were randomly allocated to class times (they don't say whether students could subsequently switch classes). This has obvious implications for students. If a student has a chance to take a class that is later in the day, they should do so. It also tells me that I should be less worried about the 5pm lecture times, and more worried about avoiding those 9am starts.