On any given day, 1,193 of the state's 12,678 public school teachers — or nearly one in 10 — are absent from the classroom.

The highest rates are at Leeward and Big Island district schools, which averaged slightly more than 11 percent of their instructional staff off each day in the first quarter of this school year. Leeward, the largest district with 2,698 teachers, averaged 298 absences a day. Big Island schools needed substitutes for 206 of its 1,846 teachers.

A report prepared for the Legislature indicated that Fridays in May have been among the highest absence days for the past two years.

"The second week of May we get smashed," said Gerald Okamoto, assistant superintendent for the state Department of Education's Office of Human Resources. "That happens to be when graduations happen."

With more than 2,000 teachers, or 16 percent, taking off the second Friday in May each of the past two years, the DOE was short of substitutes those days.

When that happens, the schools sometimes combine classes or call in resource teachers or teachers from other schools to cover the class.

"Unfortunately it means shifting the students," Okamoto said.

Fridays, in general, account for eight of the 10 highest-absence days.

As a comparison, national figures compiled by the U.S. Department of Labor show the average absenteeism rate last year for all state government employees in the United States was 4.4 percent per week. That means, during an average week, 4.4 percent of all workers were absent at least part of the time.

In the private sector, the Labor Department reports, weekly absenteeism is 3.4 percent in the service industry and 3.7 percent in production occupations.

During the first quarter of the 2004-2005 Hawai'i school year, roughly 25 percent of the absences were due to professional commitments, such as teacher development, in-service training and school-sponsored activities, according to the report.

That percentage has declined by 3 points this year and Okamoto expects a further reduction next year when the public schools move to a unified calendar.

Today, schools set their own calendars, making it difficult for the department to find times when teachers at multiple schools are free of instructional duties so they can attend training or other activities.

Once schools follow the same calendar, "We'll all be working off the same sheet of music, and what we can do, therefore, is to be able to schedule it during a period of time where we do not impact student learning," Okamoto said.

However, most absences are for other reasons. Besides sick and personal leave, jury duty, military leave and other obligations can pull teachers from the classroom, Okamoto said.

Under their contract, all teachers have 18 days of sick leave a year, five of which they can use for personal or professional purposes. Three of those five days can be split into half-days.

Okamoto said teachers are encouraged to not use all their leave, since unused days are credited toward their pensions.

Hawai'i State Teachers Association president Roger Taka-bayashi said he was not surprised by the number of absences, or the preference for Fridays, given that teachers do not get a chance to carry out personal business during normal school hours.

"We don't have time to go to the doctor, we don't have time to do any kind of business that we have to do during the day," he said. "We get in early to set up. We stay late. All the businesses are closed."

He said Fridays and Mondays tend to be the most convenient days to take off, followed by Wednesdays, which are half-days at many schools.

Since more than 22 percent of teacher absences are due to work-related obligations, Ta-kabayashi suggested that the DOE pay teachers their daily rate of pay to come in on the weekend for training. However, he noted, it is cheaper for the DOE to hire substitute teachers instead.

The DOE occasionally offers $100 per diem for teachers who attend weekend sessions, but that is even less than the $140 it costs to hire a substitute, he said.

The teachers union holds its own Saturday workshops, which are paid days and give the teachers credits toward climbing to higher pay scales. "All the teachers sign up for it. The classroom management program has a turn-away crowd," Takabayashi said.

He suspects there might be similar interest if the DOE were to offer weekend workdays instead of cutting into instructional time.

"I think the result would be astounding," he said. "I think they would ask for more."

Reach Treena Shapiro at tshapiro@honoluluadvertiser.com.