According to the National Summer Learning Association, children lose academic knowledge over the summer months and typically score lower on standardized tests at the end of summer vacation than they do on the same tests at the beginning of the summer. This loss of learning is known as "summer learning loss." Researchers at Johns Hopkins University say that during the summer months students lose an average of 2.6 months of grade-level learning in mathematics, for example. "Summer learning loss" is one of the claims of the arguments in favor of year-round education, meaning that students will benefit more without a long break in the summer. The argument suggests that teachers won't have to spend months reviewing work from the previous year, and students won't have the pressure of catching up after several months of educational inactivity.
One of the effects that year-round education has on students is that it allows more opportunities for a variety of educational experiences. From having more time to take trips outside of the classroom going to museums, onsite workplaces, factories and even college classrooms; to having more time to spend on longer term projects like growing plants; to building large-scale structures and raising animals; to being able to provide real-life experiences that apply to career paths and continuing education, this side of the argument suggests that the extended learning times provided by year-round education allow students to use additional time to understand and absorb concepts that are sometimes rushed in traditional class times.
No conclusive studies have been done that show student test scores are affected in a positive or negative manner by year-round schooling in comparison with traditional nine-month plans although there remains the belief that students in year-round schooling perform at least as well as other students. Proponents of year-round schooling, such as CNN math and science writer L. Z. Granderson, have pointed out that U.S. students pull in some of the lowest scores in the world, behind other less-developed countries and that giving a three-month vacation every summer is a contributing factor.
According to the National Association of Year-Round Education, almost 5 percent of public school students in the U.S. attend year-round schools, and there is at least some form of year-round education in each of the 50 states. However, some of distrust surrounding year-round schooling is based on a lack of belief in the ability to learn in other ways, such as over the summer, the suggestion of an interruption of family time, the proposition of scheduling conflicts and the claim that extracurricular activities will suffer.