A review panel hasn’t held charter schools accountable for student performance, and in many cases the schools are “free to spend public funds with little or no oversight,” a scathing audit of Hawaii’s public charter school system charges.

The state performance audit, released today, also found Myron B. Thompson Academy, which was the focus of a nepotism probe earlier this year, failed to “adhere to ethical fiscal management principles … (leading) to $133,000 in overpayments to staff.”

The audit concludes:

>> The Charter School Review Panel focuses on its duties as a charter school authorizer, but has delegated “core monitoring and reporting responsibilities to local school boards, effectively removing itself — and outside oversight — from the charter school system.”

>> In turn, some local school boards have “ignored their own management responsibilities, allowing schools to spend public funds without oversight.”

>> Some spending at Thompson Academy was characterized as “possibly fraudulent,” including salary overpayments that resulted in some employees being paid twice or three times what they should have been earning. The audit said that in the 2009-10 school year, the school’s elementary and secondary vice principals, part-time school administrative services assistant and part-time registrar were paid lump-sum amounts through temporary employee contracts in addition to their regular salaries.

For example, the audit notes, the school’s part-time registrar got an “administrative differential” that boosted his salary to $55,200 annually, a 212 percent increase.

The audit says Thompson’s spending practices “have the potential to erode public confidence in the school and the public charter school system as a whole.”

>> The report also found instances of “unrestrained spending,” including a school that spent nearly $18,000 in public funds on school excursions to an amusement park, ice skating rink and pizza restaurant.

Ruth Tschumy, a member of the Charter School Review Panel, said the audit’s conclusions “should be a loud call for all of us to be doing a better job.”

She added that the audit may overstate the authority of the panel, a 12-member board of volunteers, pointing out that state law considers local school boards for each charter school “the autonomous, governing body of the school.”

Tschumy also said, “We accept the recommendations that will lead to improved performance by the panel and by the schools.”

About 5 percent of public school children — or some 9,100 students — attend charter schools, which are publicly funded but are not under the state Department of Education.

Instead, their charters are overseen by local school boards, whose authority can be revoked by the Charter School Review Panel.

The state’s 31 charter schools are seen as real-life labs to test innovative approaches to education.