Maine, like most other states, has overstated its high school graduation rate, according to a new study by a national education weekly newspaper that questions the methodology states have used to come up with their figures.

Education Week, based in Washington, D.C., estimates that 30 percent of the nation’s high school Class of 2006 failed to graduate this year and that the dropout rate is underreported.

Using 2003 data, the most current available, the study found that 74 percent of Maine high school students graduated that year. That compares with a 2003 graduation rate of 87 percent that Maine reported to the U.S. Department of Education.

Christopher Swanson, director of the Education Week research center, which conducted the study, blamed the disparity in part on the hodgepodge of methods used by states to determine how many of their high schoolers actually graduate.

While states must report high school graduation rates under the No Child Left Behind Act, they are permitted to select their own calculation methods. The report found that states are using eight different methods, many of them faulty.

Maine Education Commissioner Susan Gendron said the Education Week graduation rates are probably more accurate than the state’s calculations, even though the state is using a formula approved by the U.S. Department of Education.

But Gendron said truer figures should emerge now that Maine has joined other states in a nationwide compact to determine graduation rates in the same way.

This fall Maine students will be assigned identification numbers that will allow the state to track students from school to school.

“With the model we adopted, if districts think a student is going to take more than four years, they will have to develop a plan that says when the student is going to graduate,” Gendron said.