TALLAHASSEE -- Sen. Anitere Flores has a simple fix for a complex problem.

The problem: Teachers have serious issues with the complicated new formula that will be used to evaluate them and determine pay raises. Some are being judged by the performance of students they’ve never met.

The fix, as Flores describes it: “We are going to link teacher evaluations to the students they actually teach.”

So far this session, Flores’ proposal is the lone attempt by Florida lawmakers to fine tune the controversial merit-pay program set to kick in next year. Democrats, Republicans and non-partisan education groups have praised her idea for its simplicity, and agree it’s a good starting point.

But behind the scenes, the situation is much more complicated. Teachers have doubts about the model that will determine their effectiveness. And the Department of Education must simultaneously roll out a new curriculum, tests and technology. So many questions linger that groups like the state teachers’ union and the Florida School Boards Association are urging lawmakers to hit the brakes.

“We need to slow this down now to avoid a big hullabaloo at the end of the year,” said Wayne Blanton, the association’s executive director. “We only have once chance to get this right.”

Whether lawmakers will listen remains to be seen.

Early in the session, Senate President Don Gaetz, R-Niceville, said he would support a delay. But the former Okaloosa schools superintendent no longer thinks a slowdown is necessary.

“If we don’t overcomplicate it, I think we can do it [on time],” he said.

Said Kathy Hebda, the state’s deputy chancellor for educator quality: “The state is on track for implementation in 2014-15.”

The effort to revamp teacher evaluations and pay began two years ago, when lawmakers in Florida passed the Student Success Act. The controversial law put an end to teacher tenure by requiring school systems to renew educator contracts on an annual basis. It also did away with the annual salary increases known as “steps.” Teachers hired after 2014 — and veteran educators opting into the program — will now receive raises based on student achievement.

To gauge teacher effectiveness, state education officials developed a value-added model that uses two years of testing data to predict student performance. If the student surpasses expectations, the teacher has made a contribution to the child’s growth. If the student falls short, the teacher has had a negative effect.

Local school districts are allowed to decide what constitutes an “effective” or “highly effective” teacher, and how that translates into a raise.

Teachers, however, have doubts about the model. For one, some educators believe it is fundamentally flawed because it doesn’t account for all factors that influence student performance, like whether a child had breakfast before the state exams.

In addition, only about 35 percent of teachers teach courses that culminate with a standardized test, according to statistics from the state teachers’ union. There’s no such data for the remaining 65 percent.

Making matters more complicated, the new performance-pay system is scheduled to come online as Florida adopts a new, nationally recognized curriculum known as the Common Core and a new set of standardized tests. Union leaders fear teachers won’t be fully prepared, and that it will show in their evaluations.