LISBON — The Lisbon School Committee is considering lowering the passing grade requirement — currently 2.8 out of 4.0 — at Lisbon High School.

This was the first school year with the new grading standard, and discussion Monday indicated that resentment over the standard has increased as more students are failing and confusion has grown between the School Committee and high school staff on the threshold number.

Other concerns raised Monday included scant professional development for staff on the new standard and the fact that some teachers were unaware of the revised standard.

School officials told committee members one factor contributing to the problem has been a high turnover rate among school administrators, which has led to three different passing standards — ranging from 2.0 to 2.8 — since the beginning of 2014.

Another contributing factor is differing perceptions about how to apply a 0-to-100 grading scale for tests and papers to a 4.0 scale for a final grade.

“You try to take two completely different systems and make them work together,” said Superintendent Richard Green. “That’s the issue.”

Lisbon High School Principal Susan Magee said she is seeing the freshmen class struggle with the new grading level in particular because the middle school’s threshold is 2.0.

“(The educational focus has) turned more into getting a 2.8, rather than what they’ve learned along the way,” Magee said.

The committee agreed to take the issue to the next meeting May 8.

“I wouldn’t want to see any kids not graduate or move on to the next grade because of our deficiencies,” committee member Paula Jefferies said.

The committee agreed to vote at the next meeting to lower the passing level to 2.5 for the start of the 2017-18 school year.

“It doesn’t mean that we’re dialing back the rigor,” Chairwoman Traci Austin said. “It means that the expectations are more achievable.”

The committee also discussed raising the high school’s credit requirements from 20 to 22 to break up large back-to-back study halls and to encourage students to take more classes.

The committee also suggested consolidating some classes to increase low class sizes and to create more space for electives.

Going back to 60-minute periods was also discussed. The high school currently has four 78-minute classes throughout the day. Proponents say the change would create a schedule that flows more and would allow the school to offer six classes instead of four. Teachers in general support the 78-minute periods, however, Green said.