In response to yesterday's post on the subject, a thoughtful commenter emailed me a paper -- "An Economic Explanation for the Summer School Vacation" by Dartmouth's William Fischel -- that, as its title suggests, offers an economic explanation for summer vacation. (Here's a pdf.) Fischel gives two reasons for why the summer vacation developed as it did. The first is the advent of "graded schooling" (grades had an advent!) in the late 19th and early 20th centuries:

graded schooling required regular attendance by all students, because long or frequent absences would require costly remedial attention. Thus compulsory attendance laws and a standard school year were complementary with the concept of graded schooling. Indeed, prior to graded schooling, the concept of a "school year" was not especially meaningful. Students in ungraded schools just attended until they learned whatever the teacher could offer, assuming the value of the time spent learning exceeded that spent working on the farm or elsewhere. 

So why did September become the most common start time across the nation? Fischel says this developed as migration between cities became easier, more important and more common:

Before interurban migration became important, the particular date at which school began did not matter, as long as it was the same for all schools in the district. But when new students were coming from some distance because their families were moving to a new region, school districts needed to allow sufficient time for newcomers to arrive and get settled. Losing four days of school because of a cross-town move was easily remedied, but losing four weeks of school because the family moved from Boston to Cleveland was more costly. In addition, the precise curriculum of the Cleveland school was apt to be different from that of Boston, even if both schools were graded. Even if transportation were instantaneous, a transfer between districts months after the school- year began would be disruptive. 

[...] September became the preferred time to start the school year because in the Northern Hemisphere travel is cheapest during July and August. Summer travel was least likely to be disrupted by inclement weather, and so summer became the standard time for families to move and for schools to be closed. Schools that expected many new students from outside their district would find that it paid to have a standard vacation time during which all students were idle. Interurban job-changers found that it paid to leave one's employment in summer so that they could move to another area and start their children in a new school in September. Summer remains the prime season for households to move, especially if they have children.

And, as Fischel says, there's a network effect here: If you run a school, there's a bigger benefit to starting the school year when everyone else does it, just as there's a bigger benefit to owning a telephone when lots of other people have them. All very logical. And good history!

Still, this strikes me as rather different from saying that the current regime -- with the standard three months of summer vacation -- is the optimal one. In fact, in it's own way, the Fischel paper offers a nice indictment of that system. If the best arguments for having a consistent and widespread summer vacation are just (1) the need to coordinate start times and (2) the desire to give families a few weeks to migrate and adjust, there is almost certainly going to be a better structure than the current, endless-summer state of affairs.

Olde tyme fun beach photograph from flickr user Wilmette Library History