ublic schools with diverse student populations are far more likely than those with homogeneous populations to be labeled as failing under President Bush's education law, according to a new California study.
The study examined why 3,000 of the 7,669 public schools in California were designated as "needing improvement" under the terms of the federal law, a category that obligates districts to provide transportation for students wishing to transfer to other schools and brings other sanctions in subsequent years.
The study found that many of the 3,000 schools were designated not because tests had shown their overall achievement levels to be faltering, but because a single student group — disabled learners or Asian students, for example — had fallen short of a target.
As a result, the chances that a school would be designated as failing increased in proportion to the number of demographic groups served by the school, the study found.
"The law penalizes schools that serve more diverse kids," said Bruce Fuller, a professor of education at the University of California at Berkeley who is a co-author of the study. "It's not that those schools are less effective for average students. It's just that they have all these targets to hit."
The law, known as No Child Left Behind, seeks to identify inequities by requiring schools to break down test scores for every demographic group.
If any group fails to meet growth targets or simply if its rate of test participation falls below the required 95 percent, the entire school misses "adequate yearly progress." If a school misses the goal two years in a row, it is designated "needing improvement."
The study, which Dr. Fuller wrote with John R. Novak, director of research for the Long Beach Unified School District, identified two schools in Oakland whose students, on average, performed at equal levels on standardized tests. One, Manzanita Elementary, serves a diverse population, including black, Latino, Asian, low-income and limited-English students.
The other school, Golden Gate Elementary, serves primarily black students, some of whom are also in the low-income category, giving the school just two groups under the federal law's accountability system, the study said.
As a result of its diverse population, Manzanita had to meet targets in 18 categories. It succeeded in 17.
Black students narrowly missed their target in math, the study said. Golden Gate, because of its more homogeneous student body, needed to meet targets in only six categories, and succeeded.
Manzanita was designated as needing improvement, and Golden Gate was not, the study said.
Eugene W. Hickok, acting deputy education secretary, said he was not surprised by the results in the study but disagreed with the interpretation.
"There's a certain logic that the more subgroups you have — the more boxes you have to check off — the more difficult it will be to make adequate yearly progress," Dr. Hickok said. "But to conclude that N.C.L.B. punishes diversity is a non sequitur. As a public school, you have an obligation to all your kids. If special-ed kids are not doing well, then you have an obligation to take care of that."