SAN FRANCISCO - Just how much improvement of low-accomplishing public schools have Californians purchased with the $1.25 billion in their taxes spent on No Child Left Behind special programs? The disturbing answer, apparently: “little if any academic improvement.” So reports a new study co-authored by the Pacific Research Institute and California Business for Education Excellence.

This finding is particularly troubling because it comes just when the state is about to spend another $2.9 billion of taxpayers’ money to continue the High Priority Schools Grant Program.

Titled “Failing Our Future,” the report examined student test scores at the 1,620 low-performing schools that received an average of $771,604 apiece from two supplementary funding programs over three years, as compared to scores at other low-performing schools that did not receive any additional funding.

There was “no significant difference in academic achievement over time” as measured by individual student improvement in grade-level proficiency on the California Standards Test. Yet, although these schools showed little genuine improvement, officially they are considered to have fulfilled the state’s Academic Performance Index requirements and successfully completed the extra-help program.

The PRI report — subtitled “The Holes in California’s School Accountability System and How to Fix Them” — charges that a billion-dollar wasted effort is cheating the state’s minority and low-income students by falsely measuring whether they are making real progress. The blame is placed squarely on built-in flaws of the Academic Performance Index.

The complex formula of the Academic Performance Index only measures schoolwide achievement. Therefore, as long as there are enough higher-performing students to keep a school’s average scores above the API benchmarks, the school appears to be doing well even if its lower-performing students are floundering.

Another problem with the Academic Performance Index is that its “growth” targets are set so low that any of the 3,423 California schools with a starting score below 635 could achieve the index’s required improvement every year and still need at least 61 years to raise all their students to grade-level proficiency.

In contrast, the easy-to-understand California Standards Test measures whether individual students have learned English and mathematics at the level of capability appropriate to their school grade. Those exam scores can show if significant progress is being made by all racial, ethnic and socioeconomic groups at the school.

So it is no surprise that the primary recommendation of “Failing Our Future” is for the state simply to discard the virtually meaningless Academic Performance Index and replace it with the California Standards Test, which does not mask the academic struggles of students such as those learning English as their second language.

The existing system of school accountability is actually not accountable. California is wasting billions of tax dollars on a failed school-improvement approach that leaves behind the low-income and minority children who need most help from the federal No Child Left Behind Act.