State education officials are disputing methodology used in new research that places Hawai'i's public schools in the bottom third in the country when comparing graduation rates state-by-state.

According to a report by Education Week to be released today, only 63.9 percent of Hawai'i's class of 2006 graduated on time, but state Department of Education officials say that number is incorrect. They say, according to the DOE's own calculations, that 79.2 percent of students graduated that year.

"For the past four years the department has disputed the graduation rate published by Education Week. Due to their use of the 'cumulative promotion index,' they continue to present an inaccurate illustration of Hawai'i's true public school graduation rate," said Sandy Goya, spokeswoman for the state Department of Education.

The Diplomas Count 2009 report is the most recent education policy analysis from the nonprofit Editorial Projects in Education Research Center, which publishes Education Week. This year, they estimate that the nation's average graduation rate is 69.2 percent, which is a slight decrease from last year.

Hawai'i ranked among the 15 states with the worst graduation rates in 2006, according to the report.

Among the worst performing states and jurisdictions were Nevada; Washington, D.C.; Georgia; New Mexico; and Florida, all with graduation rates less than 60 percent.

New Jersey topped the list with a graduation rate at 82.1 percent.

Currently, Hawai'i uses a "cohort" method that tracks graduation rates of individual students. That means that each year, ninth-grade students entering high school are tracked through their senior year.

Twenty-two states use the cohort method, which takes into account when students transfer out of the state or drop out of school.

Hawai'i's single statewide school system is of benefit when calculating the state's graduation rate, said Glenn Hirata, administrator of the DOE's systems evaluation and reporting section.

Because Hawai'i has the capability of following individual students statewide through a student-tracking system, Hirata said Hawai'i is able to produce the "pure" graduation rate of 79.2 percent.

"It is as accurate as we can get it," Hirata said. "It's also very conservative."

Hawai'i's 79.2 percent graduation rate is conservative in that the state's method "leaves in" students who stop showing up to school and have likely transferred out of state, Hirata said.

The method used in the Education Week report, known as a "cumulative promotion index," does not take those factors into account.

WIDE DISCREPANCY

Over the past several years, education officials have consistently disputed Education Week's and other estimates of Hawai'i's graduation rates. They say the wide discrepancies are caused by the ways the state and the report are calculating the rates.

States use several different ways to calculate their graduation rates. Because of that, beginning in 2011, the U.S. Department of Education will mandate all states switch to a methodology adopted by the National Governors Association.

For Hawai'i, the only difference in the new methodology, known as the Adjusted Cohort Graduation Rate, versus what the state is already doing, is that sudents who transfer into the school system after starting ninth grade would be included in the rate.

"It's cohort-based and very similar to what we're doing," Hirata said. "It is to our advantage."

Meanwhile, the Education Week report points out that Hawai'i has significant progress to make toward its goal of a 90 percent graduation rate by 2014 under No Child Left Behind.

"That will be a very tall order," Hirata said.