Readers of this blog will not be surprised to hear that charter schools create an enormous drain on public schools and cause damage to the great majority of children, who lose resources and teachers, so that a small number may attend an alternate school that is privately managed.

Jeff Bryant here points out that the proliferation of charter schools is more than a nuisance. It is an “existential threat” to public education.

New studies from California and North Carolina find charter schools extract millions from the public systems.

The California study, written by political economist and University of Oregon professor Gordon Lafer, looks at three large public-school systems in the Golden State and concludes the annual costs to the three districts run upwards of $142 million. The three districts in the study – Oakland Unified, San Diego Unified and East Side Union – struggle with annual deficits that have led to layoffs, class size increases, and program cuts.

The North Carolina study, written by Duke University economics professor Helen Ladd and University of Rochester professor John Singleton, finds evidence that charter schools come with “fiscal externalities,” or additional costs to the budgets of public schools. In their examination of urban and nonurban districts in the Tar Heel State, the researchers calculate an additional financial cost of about $3,500 per charter school enrollee to the Durham school district and “comparable or larger” costs to two non-urban districts.

Both studies note that additional costs imposed by charters are most apt to result in local schools cutting funding they need to maintain reasonable class sizes, well-rounded curriculums, and support staff including nurses, counselors, librarians, and special education…

As Lafer writes, “In every case [where charter schools have expanded], the revenue that school districts have lost is far greater than the expenses saved by students transferring to charter schools.”

Ladd and Singleton explain why: “If 10 percent of a district’s students shift to a charter school … the district cannot simply reduce its costs by 10 percent because some of its costs are fixed, especially in the short run.”

The NC researchers also point to costs that result from having parallel sectors of charter and public schools, which “implies duplication of functions and services (e.g., central office operations).” Also, the tendency of charter schools to open or close, often without warning, makes district budgeting uncertain and inefficient.

The costs school districts incur due to charter expansions are “unavoidable,” Lafer writes. “Because districts cannot turn students away, they must maintain a large enough school system to accommodate both long-term population growth and sudden influxes of unexpected students—as has happened when charter schools suddenly close down. The district’s responsibility for serving all students creates costs.”

Despite their protests, charter schools do not collaborate with public schools. They act more like parasites. In courts, they play both sides of the public-private issue. They are public when they demand more funding, but when sued, they are suddenly private, not “state actors.”

The attitude of the charter lobby is simple: “me-me-me.” The policy makers should not act as tools of the charter lobby. They should see the whole picture and ask whether it is wise to create a parallel school system, free to write its own rules and to drain resources from the public schools that open their doors to all students.

Despite what may have been the original intention of the charter school movement, these schools, as they are currently conceived and operate, now pose a severe financial risk to public education. Rather than operating as partners to public schools, they more so resemble parasites.

To address this growing calamity, Lafer recommends in his California study that each school district produce an annual Economic Impact report assessing the cost of charter expansion in its community, and local and state public officials take findings of these impact assessments into account when deciding whether to authorize additional charters.

Ladd and Singleton in their North Carolina study recommend states provide transitional aid to smooth or mitigate revenue losses charter school expansions impose on school districts. They point to examples of these policies in New York and Massachusetts, although they admit, “In neither case does the magnitude of the aid offset the full negative fiscal impacts of charters.”