High Quality Content by WIKIPEDIA articles! Charter schools operate with considerably more independence than traditional public schools. They are free to structure their curriculum and school environment; for instance, many charter schools fit more instructional hours into a year by running longer school days and providing instruction on weekends and during the summer. Because few charter schools are unionized, they can hire and fire teachers and administrative staff without regard to the collectively bargained seniority and tenure provisions that constrain such decisions in most public schools. Although charter students made up only 2.9 percent of U.S. public school enrollment in 2008-2009, charter enrollment has grown rapidly and seems likely to accelerate in the near future. The growth of charter schools is an important component of the contemporary education reform movement's pursuit of accountability and flexibility in public education. Proponents see charter schools' freedom...