Hawaii public school teachers were absent from their classrooms an average of 17 days last school year, and 26 percent of teachers took 10 or more sick days, according to newly released teacher absenteeism statistics that one national expert said should raise concerns.

The state data also show the number of sick days teachers took varied widely, but that the percentage of teachers with 10 or more sick leave absences tended to be higher in rural areas and communities that serve low-income students.

Why all this matters is simple, experts say: Multiple major studies have concluded that teacher absences can take a toll on student achievement, and can take a greater toll on economically disadvantaged students.

“If your teacher is absent 10 days, that turns out to be once a month,” said Raegan Miller, an education researcher who has studied teacher absenteeism for the Washington, D.C.-based Center for American Progress, a left-leaning think tank.

Miller added that substitute teachers are often tasked with focusing more on classroom management and safety than on keeping up academic rigor.

"The way that absences affect achievement is varied, but what we do have is some pretty solid evidence that the stories add up to something meaningful and real," he said. "We’re talking about educationally meaningful shocks."

The state Department of Education absentee figures, requested by the Star-Advertiser, show teachers took an average of 7.5 sick leave days in the 2011-12 school year, which Miller said appeared "high" compared with the norm.

Hawaii’s average of 17 days for all teacher absences in the 180-day school year included days teachers were out sick, on training or at school-sponsored activities, according to the DOE.

There are no national data available for 2011-12 with which to compare the Hawaii average.

But another yardstick — more than 10 absences per year for any reason — does allow comparison.

A report by the Center for American Progress, written by Miller and released in November, showed about half of Hawaii teachers had more than 10 absences, the second-highest rate in the nation. The national average was 36 percent.

Hawaii’s teachers union and state Department of Education officials said the new teacher absenteeism statistics, coupled with the November report, point to a need to get a better handle on why teachers are absent and whether there are ways to decrease teacher time away from classrooms.

Wil Okabe, president of the Hawaii State Teachers Association, said "there’s no question" that teacher absences affect student learning, but pointed out that a number of factors go into why a teacher may not be in class.

For one, efforts under way to improve Hawaii’s schools have meant more professional development and time outside of classrooms, something DOE officials also cited as a reason why teachers may be absent.

Okabe also said while it’s important to keep the number of teacher sick leave absences to a minimum, some are also unavoidable: Teachers work around children and so are at greater risk of becoming ill; or they may have to take sick days to care for their children, for family emergencies or for maternity leave. (Eighty percent of Hawaii’s teachers are women.)

Finally, Okabe acknowledged that teachers have had greater demands placed on them in recent years and that teacher morale is probably at a low point, given a protracted labor dispute with the state, all of which may also contribute to teachers taking sick leave days.

Teachers can take up to 18 sick days a year.

Ronn Nozoe, Department of Education deputy superintendent, said it’s tough to draw concrete conclusions from the teacher absenteeism numbers without more information about the absences themselves.

But he said the teacher absenteeism figures are worth digging into, in part because the DOE spends about $30 million a year on substitute teachers.

"The most important variable in student achievement is the effective teacher," Nozoe said. "The very obvious conclusion from that, of course, is that when the effective teacher is not with students, there’s going to be some impact on student achievement."

The DOE data show:

» The percentage of teachers who took 10 or more sick leave days topped 30 percent at four of Oahu’s 22 complexes: Waialua, Nanakuli, Waianae and Kahuku.

In the Kahuku complex alone, about 40 percent of teachers had 10 or more sick leave days, with Kahuku teachers taking an average of 10 sick leave days in 2011-12.

» Teachers in the Moanalua complex took the smallest number of sick leave days on average — 5.5 days. About 17 percent of Moanalua teachers took 10 or more sick leave days.

» Several individual schools also had low percentages of teachers who took 10 or more sick days. Just 5 percent of teachers took 10 or more sick days at Koko Head Elementary, Kalihi Uka Elementary, Waiau Elementary and Hanalei Elementary.

» Meanwhile, Momilani Elementary had the lowest average number of total absences per teacher at the school — at seven. Koko Head Elementary had an average of nine, as did Makalapa Elementary.

» On the other end of the spectrum, the average number of absences per teacher at Pahoa Elementary on Hawaii island was 41 days.

At Kau High and Pahala Elementary on Hawaii island, there were an average of 27 absences per teacher. More than half of the school’s 49 teachers took 10 or more sick leave days.

In his research, Miller found that every 10 teacher absences lowers math achievement for kids by the same amount as having a teacher with one to two years of experience instead of a teacher with three to five years. That’s a small but significant difference, especially when added up over a child’s K-12 experience.

While teacher absenteeism is not at the top of the list of priorities for most states — or for the federal government — when it comes to improving America’s schools, U.S. Education Secretary Arne Duncan has expressed interest in decreasing the number of days teachers are missing, and the U.S. DOE now collects data around teacher attendance.

On average nationally, teachers are absent nine to 10 days per school year for any reason.

Okabe, of HSTA, said he would be interested in sitting down with the state to talk about teacher absenteeism, and discuss such ideas as developing teacher wellness programs.

He also noted that some schools have taken on absences themselves. For example, some reward teachers with perfect or near-perfect attendance.

Nozoe said while teacher absenteeism alone is not a focus for the department, the issue undoubtedly will be part of the DOE’s larger efforts to boost teacher effectiveness and improve schools.

"We’re moving the whole thing," he said. "Changing the whole thing means taking a look at all the parts and their relationships."

Doug Murata, DOE assistant superintendent for human resources, noted the DOE is working with an outside consultant to drill into its human resources data, including its teacher absenteeism numbers.

Over the next few months, they hope to make links, he said, between teacher absenteeism and such variables as school demographics, school locations, days of the week (are absences more frequent on Mondays or Fridays?) and reasons for absence (maternity leave, personal illness, family illness, or other reasons).

Murata said the department needs better data to be able to tackle potential causes for teacher absenteeism.

"Once we isolate what’s happening, we need to understand why it’s happening," he said.