The Louisiana Department of Education will release school ratings on Thursday and, for the first time, a significant portion of the grades will be based on student growth, a metric increasing in popularity across the country.

Experts say growth is a more accurate way to measure a school’s performance than just the aptitude of its pupils, as measured by standardized test performance. Growth, which measures a student’s progress year over year, will account for 25 percent of school letter grades. The rest will be largely based on test scores, which in the past have often been the sole basis for state ratings.

“What a growth measure is trying to accomplish is to figure out the actual impact of a school on student performance,” Morgan Polikoff, an associate professor of education at the University of Southern California and an education policy expert, said. “It does that by comparing a student’s achievement in a given year based on what they’d be expected [to learn].”

“If the purpose is identifying the effectiveness of a school, then growth is much better than the typical levels we have used, which are straight achievement levels,” he said.

Polikoff said the average achievement levels at a school can vary based on socioeconomic status. “Growth can really isolate the average effectiveness of the school.”

Louisiana uses state standardized test scores to measure achievement levels. High schools are also graded on ACT scores and graduation rates.

”If the purpose is identifying the effectiveness of a school, then growth is much better than the typical levels we have used, which are straight achievement levels.”—Morgan Polikoff, University of Southern California

The main argument against growth models is that they could potentially identify poorly performing schools as proficient or that they won’t hold schools to high standards. But experts say a strong grading formula will account for those issues.

The addition of growth scores is particularly welcome in Orleans Parish, where nearly all schools are run by private charter groups that face high-stakes reviews — largely based on their state ratings — as they approach the end of their multiyear operating agreements.

The new grading system could be a boon for schools with high populations of low-achieving students who are showing marked improvement. Leaders of those schools, and others in the education community, have argued for this metric to be included for years.

At the same time, the new model isn’t expected to harm the ratings of selective admission schools — like Benjamin Franklin High School and Lusher Charter School — even though those schools may be less likely to see large student gains.

“Growth measures shouldn’t be biased against any kind of school,” Polikoff said. “In essence you’re really comparing high-achieving schools to other high-achieving schools and low-achieving schools to low-achieving schools.”

Why growth matters

Doug Harris, the executive director of the Education Research Alliance of New Orleans, said the state’s old calculation, based solely on test scores, did not take into account that students come to school at different achievement levels.

“You’re basically punishing schools serving disadvantaged students for having low scores,” he said.

In a city where test scores can determine whether a school stays open, Harris said that how schools are measured is particularly important.

“If you’ve got the measure wrong, it becomes really unfair to schools that are being measured on something outside their control,” Harris said in an interview last week.

His group conducted a study, “What gets measured gets done,” earlier this year on how schools would fare under the new grading system. It found, for example, that if student growth and graduation rates were also used to evaluate schools, then schools would value those outcomes.

”If you’ve got the measure wrong, it becomes really unfair to schools that are being measured on something outside their control.”—Doug Harris, Education Research Alliance of New Orleans

“There’s no reason not to do it,” Harris said of including growth. “It’s going to give more confidence in the measures.”

Experts like Harris say that schools will react to what is expected of them. When only static achievement levels are measured, schools will respond to that requirement.

The Louisiana Association of Public Charter Schools’ Executive Director, Caroline Roemer, agrees.

“When you are based on a system that’s solely about a test, I feared that it was providing a perverse incentive for schools to focus on certain students,” she said.

For example, she said, schools would benefit from focusing on students who were closest to making it to the next level, which would reward their school in the scoring system. That could lead teachers to ignore lower or higher performing students to focus on those who are on the bubble.

Roemer’s group supported the addition of growth to school letter grades.

“We feel like that’s a great addition to the formula and one that adds a lot of value.”

How much growth

Polikoff and Harris said states across the country are weighting growth differently, and some still don’t use the metric at all.

Harris said he’s been pushing for the policy change since 2014, when he authored a research paper for the Louisiana Board of Elementary and Secondary Education recommending the addition of growth to school grades.

The state has started by using growth as the basis for 25 percent of school grades. But Harris said the grading formula should be split evenly between growth and achievement..

Jay Altman, the CEO of FirstLine Schools, is among the school leaders who would like to see growth weighted more heavily.

“Both are important measures, and we value both,” he said. “So why don’t we weight them both equally?”

But Harris cautions about crossing a 50/50 threshold. That’s because school letter grades are based only on test scores of students in third grade and older. But Harris cautions about crossing a 50/50 threshold. That’s because school letter grades are based only on test scores of students in third grade and older. He said putting too much emphasis on growth could encourage schools to focus less on younger students.

“Unless we decide to start accounting for kindergarten scores you’ve got to pay at least some attention to achievement levels,” he said.

On Thursday, the state will release schools’ overall grades, a combination of growth and achievement, but it will also release separate “student performance” and “student progress” grades to help parents.

Polikoff thinks the two should always be kept separate.

“I think they both are good measures,” he said. “I don’t really know why you necessarily need to add them together.”

He compared it to visiting your doctor to learn your cholesterol level and blood pressure.

“I wouldn’t weight one of those and add them together,” he said. “They are presenting different pieces of information.”

State ratings and their implications

Roemer said school letter grades serve two key purposes: to show parents how schools are doing and to hold schools accountable for how well they serve students.

“We want schools to know how they are doing,” she said. “Because accountability is a tool to measure the successes they are having, and that tool then gets used to make sure we have the right resources.”

“It’s supposed to provide an incentive for schools to work hard and know there’s a judgment day.”

Fifteen schools will have their contracts reviewed by the Orleans Parish School Board next week. The school district has strongly hinted that four charter schools are likely to close and announced Monday that indeed one of them would shut down at the end of the school year. Three of the four have had several years of F ratings.

”We want schools to know how they are doing.”—Caroline Roemer, Louisiana Association of Public Charter Schools

When ratings are released on Thursday, Harris has some advice for the public.

“Pay at least as much attention to the growth measure as they pay to the other measure,” he said. “Because parents care about how much their kids are learning. And the growth measure is the one that really captures that.”

Altman also thinks parents should pay attention to both grades.

“Where would your student learn the most? Which measures student learning better?” he said.

Those letter grades, which the Orleans Parish school district has been able to roughly calculate since test results came out earlier this year, will largely determine which charter schools up for contract renewal will remain open.

Orleans Parish schools Superintendent Henderson Lewis will likely release his renewal recommendations on Monday prior to Tuesday’s Orleans Parish School Board accountability committee meeting. The full board will hear from Lewis on Thursday. But unless they overturn his recommendations with a two-thirds vote, Lewis’ decisions will stand.

Marta Jewson

Marta Jewson covers education in New Orleans for The Lens. She began her reporting career covering charter schools for The Lens and helped found the hyperlocal news site Mid-City Messenger. Jewson returned...