Each year, about 50,000 California students opt out of taking the state's basic reading and math tests. Their parents sign a waiver excusing their child from taking the tests.

That's hurting the state. The federal government requires that 95 percent of students at each school participate in those tests - or lose federal funding. Nearly a quarter of California schools have failed to meet the 95 percent participation standard. But instead of trying to reduce opt-out rates to improve the state's test participation rates, state Superintendent of Public Instruction Jack O'Connell and the state Board of Education have decided to ask the federal government to waive the 95 percent rule. They want to be able to exclude opt-out numbers from California's test participation rate.

No way. The U.S. Department of Education should refuse the California request.

The purpose of the 95 percent rule is to prevent schools from encouraging low-scoring students, the ones who need the most assistance, to stay home on test days. That's the oldest trick in the books for "improving" a school's performance.

To get a valid picture you need to have at least 95 percent of students taking reading and math tests. Otherwise the scores are unreliable measures of the performance of the students enrolled at the school.

California is one of the few states that allow parents to waive testing of their children without having to give a reason. That law passed in 1995.

These opt-outs distort school test scores - and now, with federal requirements of 95 percent participation - hurt school funding.

California has, by far, the highest opt-out numbers of any state. Where California has 50,000 opt-outs, Michigan has 1,700, Colorado 1,220, Wisconsin 435, Pennsylvania 335. Some California schools have opt-out rates of 10 percent to 20 percent - or more.

California should be focusing its efforts on getting students to attend school on the days basic reading and math tests are being conducted - and generally working throughout the school year to let students and parents know the importance of school attendance and what consequences follow if children do not attend school on test days.

Drop the idea of asking for a waiver from the 95 percent rule. That would only encourage more opt-outs, the last thing California needs as it tries to accurately gauge and address school performance.