OAKLAND — Although charter schools were intended to be an educational antidote to the city’s struggling traditional public schools, many of the city’s charter schools aren’t outperforming their district-run counterparts, and on average, performed worse last year in statewide results, according to an Alameda County grand jury report released this week.

The grand jury, which looked into Oakland Unified School District’s oversight of the city’s 37 charter schools, found that 19 scored below district averages for both charter and traditional schools in mathematics in statewide test results. And 17 charter schools scored below the district average in English. The panel reported that 15 charters scored below the district averages in both categories.

Measured against the state, the results are more troubling: 62 percent, or 23 of the city’s charter schools, scored below state averages in math, and 65 percent, 24 schools, scored below the state averages in English, according to results from the 2015 California Assessment of Student Performance and Progress, which replaced the API scores of previous years. Many of the schools performed similarly on past API tests, the report stated.

For that reason and a host of others, the panel recommended that Oakland Unified adopt a more rigorous oversight and approval process when authorizing and reauthorizing charter schools in the city. It also urged the district to increase its staffing at the Office of Charter Schools and to increase the number of on-site visits to charter schools and their board meetings to ensure stronger accountability, including fiscal and governance oversight, since they are funded on the taxpayer’s dime.

While acknowledging that other measures, such as school culture and support, must be taken into consideration alongside state test results to measure a school’s success, “it’s a concern that some charters are not achieving expected results and yet may still be reauthorized,” the panel stated in its report.

The district also should do more to ensure charter school buildings’ safety when they are located on nondistrict sites, since they don’t need to conform with higher earthquake-resistance standards, the report noted.

The district is reviewing the report and will file an official response within the 90-day deadline, said district spokeswoman Valerie Goode.

“The district remains committed to ensuring all students have access to a high-quality education and will continue our important work toward equity in our schools,” she said.

Goode said the district complies with state education code in the approval or denial of charter petitions, renewals and revocations. And it has an entire set of renewal criteria, including performance assessment, in its Charter Renewal Handbook and on the district’s website, she said.

The grand jury chose to examine Oakland’s charter schools because the district has the highest number of any city in the county. Nearly 25 percent of the city’s public school children attend charters, compared with the national average of 6 percent.

And the topic is timely, given the district’s potential adoption of common enrollment for both district-run and charter schools. The panel stated that the district should not authorize or renew charter schools unless they agree to join Superintendent Antwan Wilson’s proposed “Oakland Equity Pledge,” a compact between traditional and charter schools to adopt similar policies in terms of enrollment criteria and other issues. Critics say that charter schools can cherry-pick students and don’t have to play by the same rules as traditional public schools when hiring teachers and enforcing expulsion policies.

“Although 87 percent of the district’s charter schools have signed on (to the Equity Pledge), they are not required to participate,” the report says.

But Emily Bertelli, a spokeswoman for California Charter School Association, took issue with the jury’s report. She said it’s unrealistic to ask charter schools to sign on to the Equity Pledge because it is not yet finalized. She also noted that charter schools have their own governance and oversight and are at a disadvantage when finding equitable and affordable facilities, since they rarely have access to local school bonds or parcel taxes that benefit traditional schools.

“CCSA disagrees with many of the assertions laid out in this report,” she said. “We find the report lacking understanding of the depth and nuance in both law and practice of charter schools across California. Furthermore, the report is oversimplified in both its definition of the issues and recommended solutions.”

To read the report, go to https://www.acgov.org/grandjury/final2015-2016.pdf.

Contact Joyce Tsai at 925-945-4764. Follow her at Twitter.com/joycetsainews.