Thirty-six years after the California Supreme Court ordered the state to fix its unequal system of funding schools, a gaping disparity remains between haves and have-nots.

And it may not improve much any time soon.

A scathing report on California’s school finances not only repeats the indictment of an inequitable, insufficient and irrational funding scheme, but also details how California spends on average $620 less on a student living in a high-poverty area than one in an affluent neighborhood.

The report by the Education Trust-West, an Oakland-based education advocacy group, also attacks the complexity of California school financing. “The system is a haphazard collection of arcane and hard-to-navigate policies that manage to hide funding disparities from district leaders and policy makers, not to mention parents and the public,” the report, released last week, reads. “The maze of programs and formulas makes it nearly impossible to understand whether dollars ever reach the schools and students for whom they are intended.”

A yawning gulf separates even school districts serving students from similar demographic backgrounds. For example, in 2009-10, the latest data available, per-pupil revenue was $14,076 in Palo Alto versus $7,679 in Milpitas, both unified districts serving K-12 students. But clearly, affluence counts: In San Mateo County, the Woodside elementary district took in $18,894 per student, while Millbrae elementary got $7,362 per student.

But it’s not always the case that districts serving poorer students take in less. Ravenswood City School District in struggling East Palo Alto received $12,119 per pupil, while the affluent area served by the Cupertino Union School District received $7,335 per pupil.

Those figures include federal, state and local revenue reported to the state Department of Education. That means that local parcel taxes and foundation grants were counted, but funds contributed by parent groups may not have been. The Education Trust-West report excluded federal revenues because it aimed its report at state policymakers, said Carrie Hahnel, the group’s director of policy and research.

In the 1976 Serrano v. Priest case, the California Supreme Court ruled that the state’s system of school funding, then based on local property taxes, was inequitable and unconstitutional. In 1979, Proposition 13 reduced local property taxes, and funding of schools shifted sharply to the state. As a result of the ruling and the tax initiative, California’s school funding plan evolved into a complicated set of formulas. When voters passed Proposition 98 to set a funding floor for education, formulas became more complex.

As the recession has cut into the state’s finances, local fundraising has increased in affluent areas and heightened the disparity in education funding, the report noted. “The impact of that is fairly significant in determining the size of the gap,” said Arun Ramanathan, executive director of the Education Trust-West.

While he praised Gov. Jerry Brown’s proposal to revise funding formulas as “a step in the right direction,” he said he fears that there’s no assurance that the neediest schools and students will receive the money.

“The state has a responsibility to ensure that districts are addressing those students with higher needs and to come up with accountability systems,” Ramanathan said.

Brown has proposed a funding formula that gives weight to students’ needs, so schools with more poor students and English language learners would get more money.

Contact Sharon Noguchi at 408-271-3775. Follow her at Twitter.com/NoguchiOnK12.