The Berlin School Committee has unveiled a new attendance policy for the town’s elementary school in light of problems with absences during the current school year. The new policy stipulates that Berlin Memorial School students can only miss five school days per trimester. Once they miss three days, a letter is sent to parents. After five absences, the student and his or her parents must meet with school staff. The average number of absences this year is nearly seven, according to a letter to parents from the school’s principal, John F. Campbell Jr. In enforcing the policy, school officials emphasize that classroom attendance at a young age is a key building block to students’ performance later in life. Full story for BostonGlobe.com subscribers.