Oregon Revised Statutes Education and Culture § 339.065

(1) In estimating regular attendance for purposes of the compulsory attendance provisions of ORS 339.005 to 339.030, 339.040 to 339.125, 339.137, 339.420 and 339.990, the principal or teacher shall consider all unexcused absences. Eight unexcused one-half day absences in any four-week period during which the school is in session shall be considered irregular attendance.

(2) An absence may be excused by a principal or teacher if the absence is caused by the pupil's sickness, by the sickness of some member of the pupil's family or by an emergency. A principal or teacher may also excuse absences for other reasons where satisfactory arrangements are made in advance of the absence.

(3) Any pupil may be excused from attendance by the district school board for a period not to exceed five days in a term of three months or not to exceed 10 days in any term of at least six months. Any such excuse shall be in writing directed to the principal of the school which the pupil attends.