First of all, up until the late nineteenth century, the school year, especially in the cities, was actually all year long. This was driven by the desire to have the kids in school so their parents could work, especially in factories. In rural areas, kids were given release time in the spring and fall for planting and harvesting - not "summer vacation" to work in the fields. The "agrarian model" explanation is a myth, and up-to-date education researchers have known this for years. The school calendar was not set so kids could help on the farm. Most of the work on a farm is done during spring and fall - planting and harvesting. Clearly, that is when the kids were most needed. The summer vacation schedule was set to appeal to middle and upper class families (the ones who actually went beyond sixth grade) because these families wanted to get out of the hot, crowded cities (and classrooms) during the summer months, especially before the days of air conditioning.
The "myth of summer vacation" has been well-documented over the years, though misperception persists. Perhaps the most informative analysis of the history comes from a really good read by Kenneth Gold, entitled School's In: The History of Summer Vacation in American Public Schools.
While there are arguments for longer school, the agrarian model is not one of them. Additionally, the longer school day has shown a definitive impact in struggling, urban populations, but suburban middle and upper class populations have never shown the "summer loss," and they are well-served by a myriad of summer activities that enhance and add to their education as well-rounded citizens in ways that more classroom time drilling for standardized tests doesn't. If we are going to have effective discussion about education reform, we need to dispense with the perpetuation of myths by the misinformed. Additionally, the article I linked to noted that the belief that others countries' students spend more time in school is also not true:
While it is true that kids in many other countries have more school days, it's not true they all spend more time in school. Kids in the U.S. spend more hours in school (1,146 instructional hours per year) than do kids in the Asian countries that persistently outscore the U.S. on math and science tests — Singapore (903), Taiwan (1,050), Japan (1,005) and Hong Kong (1,013). That is despite the fact that Taiwan, Japan and Hong Kong have longer school years (190 to 201 days) than does the U.S. (180 days).
As I noted after watching the movie Two Million Minutes, critics have argued that by the time they graduate from high school, Chinese and Indian students will have spent twice as much time in school as American students. But that leads to the following questions:
Are their economies twice as large or powerful? Are their buildings and bridges twice as strong? Are their doctors and scientists twice as effective and efficient and innovative? Are their products twice as durable? Are their workers twice as productive?
The answer is, of course, no.
Arne Duncan and President Obama need to do a little more research before they start speaking of reform in education. Clearly, there is evidence that a longer school day, week, and year is helpful for struggling populations. However, my high school has a 90% school-wide pass rate on AP exams in nearly all subjects, and we have more honors classes than regular levels. And we do it with the current schedule.
If anything, our students can get through K-12 effectively in less time, not more.