• Photo gallery: Kualapuu School on Molokai

As the number of students in Hawaii’s charter schools grows, so has concern about oversight of these diverse campuses that rely on public money but are exempt from many state regulations.

Designed as laboratories for innovation in public education, charter schools now educate 9,000 children across the state, a nearly 50 percent jump in the past three years. Many of the state’s 31 charter schools are in rural areas, tucked largely out of sight and out of mind. Other than their devotees, few people know much about them. But that might soon change.

The spotlight is shifting to these "schools of choice" that now educate about 5 percent of Hawaii’s public school children under "charters," or contracts with the state. Sixteen years after Waialae Elementary became Hawaii’s first charter school, the state auditor is conducting a performance audit of the charter school system, due out this summer.

"Given the kinds of problems we’re starting to see, and the questions that were coming up, now that the schools have been in operation for a while, how accountable are they for their own performance and for their students’ performance?" asked state Auditor Marion Higa. "With the increase in their enrollment, and the increasing pressure the schools were exerting for facilities money, I thought this might be a good time to take that up."

Charters were created as a means of reform in public education, with high hopes of developing new techniques to lift academic performance where regular schools had failed. While some charters have done so, charter schools as a whole appear to be doing no better than traditional public schools with similar populations, and by some measures are faring worse.

Legislators and members of the Charter School Review Panel are sharpening their oversight. Rather than simply getting their charter, starting this fall charter schools must go through reauthorization every six years to ensure they are on track academically and financially. And for the first time, each charter school was required to submit an independent financial audit this year.

"Expectations for charter schools have changed over the past decade," said Ruth Tschumy, chairwoman of the review panel, which was formed in 2007 to take on oversight of charters from the Board of Education. "In the early years, charter schools were used to operating in somewhat of a vacuum as they struggled to survive.

"Many charter schools are now 10 years old, and it’s time for them to shine as quality schools with innovative educational programs and practices," she said. "If there are a few schools where that isn’t happening, then it’s up to all of us in the community to help them achieve their potential."

Trying to assess the overall performance of charter schools is tricky. It’s tough to generalize about campuses that vary so dramatically — from a tiny Kauai schoolhouse that educates 37 students in the Niihau dialect of Hawaiian to Waipahu-based Hawaii Technology Academy, the largest, whose 1,000 students do much of their work online.

Still, as public schools they are subject to state and federal testing and reporting requirements, which allow for a snapshot of their academic performance and their student profile. According to the most recent data, charter school students perform on par or slightly better in reading than other public schools in Hawaii but do notably worse on math. Overall, charters serve fewer pupils with language barriers and other hurdles to learning.

On the 2010 Hawaii State Assessment, 68 percent of charter school students and 67 percent of all public school students scored proficient in reading, a virtual tie. In math, however, public school students as a whole did better, with 49 percent proficient compared with 40 percent of charter students.

A higher ratio of regular public schools also made "adequate yearly progress," the federal benchmark for success. The figures were 51 percent for all public schools, compared with just 39 percent for charters last year. Graduation rates were the same for both sets of schools, with 79 percent graduating on time.

Some charter schools have succeeded in rescuing students who had stalled in regular public schools and were ready to give up. But as a group, charters appear to have an easier population to educate. There are more than twice as many children learning English in the overall public school population, at 10 percent of the student body, than in charter schools, where they make up just 4 percent. Regular public schools also serve more special-education students than do charters, as well as slightly more low-income students, according to state data.

A national assessment by the Center for Research on Education Outcomes at Stanford University found that 17 percent of charter schools reported academic gains significantly better than traditional public schools over time, while 37 percent of charter schools did worse than their traditional school counterparts. The rest showed no significant difference. The study, released in 2009, covered more than 70 percent of the nation’s students in charter schools, with controls for student demographics, economic background and special education.

Charter school advocates say their performance is remarkable considering the hurdles their campuses face, including a lack of money for facilities, shrinking funding on a per-pupil basis, and difficulty recruiting teachers reluctant to lose their seniority in the Department of Education. As charter enrollment has shot up and the economy contracted, state funding per pupil has slipped from a high of $8,596 in the 2007-08 school year to just $5,560 this school year.

"Charter schools do operate at a significant disadvantage because we don’t get support for facilities, in a place where leases, rents and mortgages are the large part of your budget," said Lynn Finnegan, executive director of the Hawaii Charter School Network. "It could be upwards of 30 percent of operating costs for a charter school to operate. They are doing much more with a lot less."

While average test scores and student demographics offer a big-picture image of charter schools, they obscure the individual portraits of each school, which vary widely.

"We are 31 unique schools," said Mark Christiano, executive director of Kihei Charter School, the only charter on Maui. "It wasn’t supposed to be a system. It was supposed to be independent local school boards, doing the best they can to innovate. Sometimes it’s working really well and sometimes it’s not."

His campus, with 529 students in kindergarten through 12th grade, has dramatically improved performance in math. Reading scores are high, at 77 percent proficient, while math scores have jumped steadily each year, reaching 50 percent proficient last year, up from 24 percent in 2007.

"We still have quite a way to go," Christiano said. "We really have focused on STEM education — science, technology, engineering and math. It’s sort of a math-all-day-long approach. We try hard to integrate math into the science activities, having students use math in a way that’s hopefully motivating and exciting for them."

Meanwhile, at Halau Ku Mana, a Hawaiian-focused charter school in Makiki Valley with 66 students in grades 6 through 12, math scores remained stuck near the bottom of the heap for the past few years. Just 9 percent of students were proficient in 2010, the same as three years earlier. Its reading scores are much better, at 60 percent proficient. Many of its students face challenges: It has the highest percentage of special-education students of all the charters, and two-thirds of its students are economically disadvantaged.

Executive Director Patti Cronin, who was hired last July, said the school realized its math scores were "unacceptably low" and has moved aggressively to boost performance this year. The staff began working intensively with students one on one, offering math camps outside of school. It uses a supplemental software program and emphasizes homework and a positive attitude.

Two weeks ago the campus erupted in jubilation when results from the latest round of online testing showed a huge jump, to 40 percent of students proficient in math.

"It was a total effort from top to bottom," Cronin said, "and we just have to keep that momentum going."

Over the past decade, charter schools in Hawaii have given parents more choice in public schooling, and have developed some attractive new approaches to education. The goal of the movement, advocates say, is to nurture the successful models and help spread their techniques to the broader population.

"We want great schools for every kid in Hawaii," said Christiano, Kihei Charter School’s executive director. "The question is how do we push these great models and get them to work for all kids? We need our good ones to happen more often."