New research places Hawai'i among the top states in the nation to show great improvement in high school graduation rates, while about 75 percent of states showed no improvement.

In 2006, Hawai'i's public schools graduated 3.4 percent more high school seniors than they did in the previous four years, according to the research conducted by Johns Hopkins University. The report recorded Hawai'i's graduation rate in 2006 at 76 percent.

Hawai'i was among only 11 states to show improvement in graduation rates, according to the report. Even so, state Department of Education officials disputed the findings, saying they're based on "quite flawed research methods."

For nearly a decade, Hawai'i's graduation rate has remained steady at about 79 percent, said Glenn Hirata, administrator of the DOE's systems evaluation and reporting section.

Hirata said the methods used in the study to calculate graduation rates and any supposed gains are flawed.

"It's basically a guesstimate based on easy-to-attain data. Their methods would not be acceptable under No Child Left Behind or federal reporting," he said.

Hawai'i uses a "cohort" method that tracks graduation rates of individual students. It takes into account students who transfer out of the system. Hawai'i's method even leaves in students who stop showing up to school and have likely transferred out of state, Hirata said.

"Our 79 percent is actually a conservative number," Hirata said.