Having digested the implications of a new merit pay plan for educators in Tennessee’s largest school district, Shelby County’s teacher association is asking the district to test the plan for three years and renegotiate its terms.

The district has promised only to seek input from teachers in finalizing the plan, which takes effect for the 2015-16 school year.

The new performance-based pay plan, which was presented Dec. 16 to the Shelby County School Board, is designed to reward teachers for the results they produce in the classroom and not just for additional years of service.

More than 300 teachers attended an informational meeting on Thursday organized by the Memphis-Shelby County Education Association. The association distributed information packets and urged its members to contact school board members with their concerns. The board meets again on Jan. 27.

Under the previous plan, teachers received $950 to $1,200 in “step” increases based on years of service. The new plan, based on a five-point evaluation scale, awards increases ranging from $800 to $1,200 to teachers reaching the top three levels of performance. Performance levels are based on state-approved evaluation criteria.

Ken Foster, executive director of the teacher association, discounted the new plan as unsustainable. “A school system has to limit the number of teachers at the top level in order to financially maintain the pay plan,” he said on Friday. “It never works. They either are going to make the higher levels too high, where only a few can reach, or limit the number of teachers at the 3, 4 and 5 level.”

The association is advocating for continued “step” raises and cost-of-living increases for the district’s 8,000 teachers.

Shelby County Schools is relying on the new plan to help recruit and retain top teachers. Under the plan, a teacher’s starting salary is $42,500. The top range is $70,000.

Superintendent Dorsey Hopson emailed all teachers on Thursday assuring them that their current salary cannot be reduced under Tennessee law. “The district’s new compensation plan . . . ensures that teachers are rewarded with pay raises for effectiveness in the classroom,” he wrote. “Rolling out this updated compensation plan is the district’s first step in ensuring that teachers are properly and fairly compensated with salaries that are comparable to those of other metropolitan districts.”

The new pay plan was prompted by revised guidelines passed in 2013 by the state Board of Education. The state required districts to create new pay schedules based on criteria such as a high classroom performance, working in high-needs schools or subject areas, and taking on additional responsibilities.

Shelby County is among the last districts in Tennessee to develop its new plan due to the 2013 merger of Memphis City and Shelby County schools, as well as the subsequent creation of new school districts in six suburban cities near Memphis.

Meanwhile, teachers are trying to discern what the new plan could mean for them individually in a district that has not awarded pay increases for three years due to budgetary restraints, although it did award performance-based bonuses last year ranging from $250 to $1,250.

“I think it’s better than what we’ve had the last few years, and it does add to our salary for the next year,” said Jeffrey Mister, an eighth-grade math teacher at Airways Middle School in Memphis.

Special education teacher Telesa Echols, who also works at Airways Middle, dislikes the performance-based pay plan, however. “It’s a bad idea,” she said. “Those scores are based on human perceptions, and what if the evaluator does not like you? I believe our raises should be based on so much more like attendance, preparations and contributions to school environment, community and the person’s overall worth to the district.”