National Alliance for Public Charter Schools president Nina Rees (WIBC.com photo: Eric Berman)

National charter-school leaders are congratulating Indiana school operators on their growth -- and warning they've got to deliver.

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The National Alliance for Public Charter Schools says an expansion of charter schools enacted last year gives Indiana one of the strongest charter laws in the nation. But president Nina Rees cautioned told 100 Indiana charter operators at their annual conference they'll be under the microscope from skeptics to see if they deliver on their promises of providing a better education.

United Negro College Fund president Michael Lomax, who serves on the alliance board, says charters need to embrace what Rees says is their critical advantage over traditional public schools: the ability to shut down schools that aren't performing.

Indianapolis Mayor Greg Ballard has revoked the charters of two Indianapolis schools, including The Project School in July.

Lomax says charter schools aren't the whole solution, but they are a piece of it. He says charters must be sure they serve a diverse population -- he says they can put to rest the notion that students from poor neighborhoods can't excel.