National experts told Indiana education leaders Thursday that the state’s plan to give schools two A-F grades for the foreseeable future is unsustainable — and that parts of both grade models could be problematic going forward.

Indiana ended up with two school grading systems after state education officials updated the state’s rating method in response to new federal law. But Indiana State Board of Education members decided they were ultimately unhappy with that combined system and decided to peel off a state version, a move that has complicated the entire process.

This year, both systems are in effect, meaning schools can expect two grades — one federal, one state — in 2018 and potentially longer. And experts testified Thursday that this will likely lead to a lot of confusion for schools, teachers, and parents.

“I don’t think it’s in the state’s best interest to go a really long time … with two grades,” said Patricia Levesque, CEO of the the Foundation for Excellence in Education, a nonprofit founded by Florida Gov. Jeb Bush in 2008. The group consults with states about accountability systems and how to improve them.

Read: Indiana has a curious plan to sidestep federal rules — give schools two A-F grades

State education leaders asked for the input from national experts in March, when they unexpectedly decided to pause the redesign of the state grading system. Leaders have been working to overhaul the grading system since the federal law passed in late 2015 but can’t agree if the state should keep its current model created in 2016, update that model, or merge with the federal model written in 2017 to comply with the federal Every Student Succeeds Act.

Levesque said Indiana’s grading systems were pretty good, but they could use better measures for progress and avoid other methods that are less reliable.

Board members were mixed in their responses to Levesque’s critique. At Thursday’s board work session, they appeared ready to go back to the drawing board, but at times they fell into old debates about which was more important — the state’s system or the federal government’s.

That’s been typical of the whole overhaul process, which has been bumpy with little consensus. The state board and Indiana Department of Education officials, responsible for creating the federal plan, have frequently butted heads during A-F discussions about what to include and whether it ultimately matters if Indiana schools get two grades.

The state and federal grading methods for calculating school ratings have key differences. The federal grade would include school attendance rates and language proficiency of English-learners, while the state calculation would mainly rely on state test scores and test score growth. Additionally, Indiana’s calculation excludes certain students that the federal plan includes, such as those receiving credit recovery services, so the final ratings could differ significantly for the same school. Although state and federal accountability metrics have differed in the past, the differences going forward would be more significant.

State Superintendent and board chairwoman Jennifer McCormick urged the board to think about the difficulty of maintaining two separate grading systems and the importance of cooperating with the federal government. Whether Indiana chooses one model or two, she said, the federal rules can’t be ignored because they determine, among other things, significant grant funding for teachers and poor students.

“We don’t have the capacity to do it all and do it all well,” McCormick said. “That’s the benefit of one system.”

Tony Walker, a board member who represents parts of Northwest Indiana, said the federal system is “antiquated” and focuses too much on state tests, which can’t capture what’s really happening in schools.

Levesque said at the end of the day, state leaders need to figure out what they’re going to tell the public — especially in the likely scenario where one school gets two different grades in one year.

Her presentation also included advice on how the grade calculations themselves should change and what pitfalls Indiana can avoid.

Grades shouldn’t pit schools against each other

In Indiana, letter grades have two main components: Test scores and how much students improve on tests each year, known as growth. Levesque said Indiana uses what is called “normative” growth, which means a school’s growth scores are calculated in relationship to how other schools do. That’s a problem, Levesque said, because it makes schools responsible for things they can’t control.

“They are a zero-sum game,” Levesque said. “There are always winners and losers when you’re doing comparisons.”

Instead, the state should consider “criterion-based” growth, she said. That’s a measure of how well schools do based on a specific yardstick — every school could get top marks, and every school can see what it needs to do to hit the next level.

How to measure growth is not a new debate in the school ratings world — and it can get pretty controversial. Although Indiana’s switch from ISTEP to ILEARN next spring complicates its ability to change growth models, it’s not impossible if state officials start planning now, Leveque said.

Avoid metrics that can be “gamed”

Indiana’s federal ratings are determined, in part, from school attendance data, and could factor in surveys of parents, teachers, or students down the road. Levesque said these metrics, along with other participation-based measures for things like fine arts classes or advanced courses, can easily be manipulated and lead to harsh policies on the ground.

For example, if attendance is part of a school’s grade, principals could restrict excused absences. That can put a lot of pressure on parents and teachers if family events or other situations arise that require students or teachers to miss school.

Some surveys, though, can be useful tools for states interested in incorporating such measures in school grading. Back in 2016, researchers presented to Indiana’s board a survey used in Chicago called the Five Essentials, developed by UChicago Impact, a nonprofit group affiliated with the University of Chicago, but the survey hasn’t resurfaced in subsequent conversations about A-F grading, and Levesque said using a similar model could be costly.

A-F grades aren’t the ‘end-all, be-all’

Levesque, and Ryan Reyna, director at Education Strategy Group who also presented to the board, reminded board members several times that letter grades don’t have to include every facet of a student’s learning. There are other ways for the state to show it values things like work-based learning and social-emotional learning.

“Your accountability system doesn’t have to cure everything,” Levesque said.

The experts also cautioned the board to take things slowly — introducing new measurements into a state grading system should happen only after data has been collected for a few years and analyzed.

But Indiana policymakers aren’t necessarily known for taking things slowly. Almost every year since the state adopted new academic standards, there have been major changes to state tests, letter grades, or both.

McCormick said she appreciated the reminder that letter grades are just “one piece of a complex puzzle,” not “the end-all, be-all.”

The board is set to have up to four more work sessions on accountability in the coming months.