There are politicians who are pushing for year-round school or increasing the length of the school year. Michigan recently passed a law that requires the school year to be 180 days despite earlier laws which don't allow schools to start before Labor Day and that lengthened the school day, trying to make the school year end before Memorial Day. Yet these ideas aren't not supported by data.
Take colleges and universities for example. Seat time in classes is only two-thirds that of high school classes in any given week, and there are usually fewer classes in that same week. Yet college courses get through more information in a single semester than most high school (let alone lower level education) classes. Districts with year-long school years have shown little difference in their scores to schools that follow the traditional calendar.
People pushing for more seat time are under the mistaken impression that other countries are giving their students more hours of instruction. This is quite simply not the case. In fact, high performers in the world such as Finland have significantly fewer instructional hours than the U.S. One could almost, almost, make the assertion that fewer hours of seat time equates to greater learning.
The simple fact is that learning is based on the motivation of the learner and the value that a given culture places on education. Socio-economic status also plays a large role in the time that parents can give to their children. While good teachers and solid schools are important to people's education, believing that simply increasing the amount of time that people spend in them will make them smarter is a fallacy.