schools." Chartering authorities Chartering authorizers, entities that may legally issue charters, differ from state to state, as do the bodies that are legally entitled to apply for and operate under such charters. In some states, like Arkansas, the State Board of Education authorizes charters. In other states, like Maryland, only the local school district may issue charters. Some school districts may authorize charter schools as part of a larger program for systemic improvement, such as the Portfolio strategy. States including Arizona and the District of Columbia have created independent charter-authorizing bodies to which applicants may apply for a charter. The laws that permit the most charter development, as seen in Minnesota and Michigan, allow for a combination of such authorizers. As of 2012, 39% of charters were authorized by local districts, 28% by state boards of education, 12% by state commissions, with the remainder by universities, cities and others. Caps Andrew Rotherham, co-founder of Education Sector and opponent of charter school caps, has written, "One might be willing to accept this pent-up demand if charter school caps, or the debate over them, were addressing the greater concern of charter school quality. But this is not the case. Statutory caps as they exist now are too blunt a policy instrument to sufficiently address quality. They fail to differentiate between good schools and lousy schools and between successful charter school authorizers and those with a poor track record of running charter schools. And, all the while, they limit public schooling options and choices for parents." Demographics The U.S. Department of Education's 1997 First Year Report, part of a four-year national study on charters, was based on interviews of 225 charter schools in 10 states. The report found charters tended to be small (fewer than 200 students) and represented primarily new schools, though some schools had converted to charter status. Charter schools often tended to exist in urban locations, rather than rural. This study also found enormous variation among states. Charter schools tended to be somewhat more racially diverse, and to enroll slightly fewer students with special needs or limited English proficiency than the average schools in their state. Funding Charter school funding is dictated by each state. In many states, charter schools are funded by transferring per-pupil state aid from the school district where the charter school student resides. Charters on average receive less money per-pupil than the corresponding public schools in