While no South Florida schools have been formally accused of excluding children, there have been problems elsewhere: Last July, the Academic Leadership Charter School in New York City was put on probation after hundreds of children were left out of the admissions lottery. One year earlier, an Albany, N.Y., charter school screened out children who had low test scores or learning disabilities.

In Florida, state and federal rules bar charter schools from giving preference to students except in narrow circumstances. For example, nearly all charter schools in South Florida give preference to the children of employees and the siblings of current students. Those run by municipalities can also give preference to residents.

Some schools, however, have created their own rules.

Coral Reef Montessori gives preference to children who have previous Montessori experience, principal Lucy Canzoneri-Golden said. (Many of those children graduate from the pre-kindergarten Golden operates on the same campus, she said.) But Coral Reef’s charter — its contract with the school district — says nothing about any preference for prior Montessori experience.

Some schools have created “articulation agreements” with other charter schools, giving preference to students as they advance from one charter school to another. Nothing prohibits a Florida charter school from having a relationship with another school, but the process is frowned upon by federal education officials. The guidelines for receiving federal grant money say charter schools receiving federal start-up grants are not allowed to give preference to students from “affiliated” schools.

Location, location

The location of a charter school also plays an important role in dictating its racial and socioeconomic makeup.

In Miami-Dade, charter schools have proliferated primarily in the suburbs, while inner-city and black communities have remained largely neglected. Last year, one in four traditional public schools were in a neighborhood where at least one-third of the residents were black, a Herald analysis found. But only one in seven charter schools were in a neighborhood with a similar makeup.

Of the charter schools that have closed in Miami-Dade County, 20 out of 30 were in predominantly black neighborhoods.

Experts say charter schools in the inner-city face unique challenges.

Katrina Wilson-Davis, who served as founding principal of the Liberty City Charter School, said finding a building for a school in the urban core can be difficult. There’s also the challenge of trying to balance a school’s budget in a low-income community.

“Our parents cannot give us money to supplement our budget,” Wilson-Davis said. “Our parents don’t have the time to volunteer in the office every day. We have to pay for everything.”

Despite solid academic performance, Liberty City Charter School closed in 2008, after falling more than $1 million in debt.

As for transportation — a concern for black lawmakers in 1996 — records show it is provided by only 40 percent of Miami-Dade charter schools.

Haag, the consortium president, said he “strongly” encourages charter schools to provide transportation for their students. “Buses remove the barriers,” he said.

State Rep. Dwight Bullard, a Miami Democrat who sits on the House Education Committee, said charter schools have a responsibility to serve all children. “From a moral standpoint, they should be investing their time, energy and efforts into communities that need the most help,” he said.

To that end, the state education department and the Charter School Growth Fund recently rolled out a $30 million fund to help high-performing schools expand into high-poverty neighborhoods.

“We’ve made it a priority over the last year to incentivize our highest-quality operators to go into our highest-poverty areas,” said Miller, the state charter schools director.

Efforts to increase diversity have taken hold in individual schools, too. Keys Gate Charter School and Keys Gate Charter High in Homestead, for example, sent out mailers to homes within a 10-mile radius of the school in hopes of attracting students from across South Dade. The two schools also placed advertisements countywide.

The strategy is working, Keys Gate officials said. This year, 64 percent of students qualified for free or reduced-price lunches, up from about 54 percent the year before.

“The diversity has increased beyond the neighborhood,” said Hage, whose company manages the schools. “It is more and more reflective of the city and beyond.”