Ohio school districts are graduating fewer students than they claim and the number of kids earning a diploma is on the decline, according to a nationwide report released yesterday.

The Columbus Public Schools are among the worst over-reporters in the county, graduating just 41 percent of students in the 2003-04 school year, the report said. District and state officials maintain that Columbus schools' graduation rate was 61 percent that year.

"We stand by our graduation rates," said Karla Carruthers, a spokeswoman for the Ohio Department of Education. "Using our calculation, (Ohio's) graduation rate has increased eight years in a row."

The annual report, called "Diplomas Count," calculated graduation rates for every school district and state in the country based on federal data from the 2003-04 school year, the most recent year available. The study was conducted by the Maryland-based Editorial Projects in Education Research Center and Education Week, a newspaper reporting on American education.

According to the "Diplomas Count" report, Ohio's graduation rate fell from 76.5 percent to 74.7 percent between the classes of 2003 and 2004. Nationally, the graduation rate increased from 69.6 percent to 69.9 percent during that period.

The report's authors contend that Ohio's calculation method -- called the Leaver Rate and used by a majority of states -- underestimates dropout rates and inflates graduation rates.

The method assumes any student who withdraws from a district graduated from another school, unless the district chooses to identify the student as a dropout.

Christopher Swanson, director of the EPE Research Center, called the method "highly problematic."

Conversely, the EPE Research Center's method, called the Cumulative Promotion Index, essentially attributes any reduction in class size to dropouts.

Both methods have limitations. Ohio's method allows districts to independently report how many students dropped out, leaving "some risk of manipulation," explained Matthew Carr, education policy director for the Columbus-based Buckeye Institute for Public Policy Solutions.

"The best way to look at it is the CPI Index is a bit low ... and you expect the state number to be a bit high," Carr said. "I expect the real number to be somewhere in between."

But in some cases, the gap between the two numbers is huge.

According to "Diplomas Count," Ohio's graduation rate was 75 percent and declining in the 2003-04 school year. But according to the state Department of Education, it was 86 percent and on the rise.

Columbus schools showed an even larger discrepancy: 41 percent, according to the report, 61 percent, according to the state.

Columbus schools spokesman Jeff Warner said the district had not seen the report. But he said the difference likely is because the report did not account for the high number of students who left the district for charter schools and other public school districts.

"Urban districts have very high mobility rates. So if they are not factoring in mobility, that will have an impact on that calculation," Warner said. "As well, when you look at the number of charter schools that we have in the Columbus metropolitan area, that affects the students that stay with us."

Other Ohio urban school districts had similar differences in the graduation rates. The state put Cleveland's graduation rate at 50 percent; the report put it at 34 percent.

The discrepancy is worst in Toledo. There, just 37 percent of students earned a diploma, according to the report. But the state says the graduation rate is more than double that --77 percent.

ssebastian@dispatch.com