A key part of state Superintendent of Education John White's plan to overhaul public schools was criticized Wednesday by nine education and business groups, including traditional allies of White.

The disputed points were spelled out by the Louisiana Association of Business and Industry, the Urban League of Greater New Orleans and the Southern Poverty Law Center, among others.

The key criticism is White's plan to change the way public school letter grades are calculated.

Under current rules, school performance scores that shape the grades are based mostly on high-profile test results.

White wants to change that so 25 percent of the score would stem from annual academic growth, regardless of the final score.

The superintendent and others contend academic gains have long been neglected in calculating all-important letter grades for elementary and middle school students.

The Louisiana Accountability Commission, after months of talks, endorsed White's recommendation last week.

But LABI and other members of the coalition said allowing 25 percent of letter grades to stem from yearly gains in the classroom is too much. "We believe the state should focus on the actual achievement of students," according to a three-page statement issued Wednesday.

"While we applaud the progress that educators and schools are able to make with students, over emphasizing student progress is misleading to parents and the public about the performance of the school," the groups said.

"Measures of test performance should be based predominantly on whether students are meeting or exceeding state standards," the statement says.

The issue represents one of the chief controversies on how the state plans to revamp letter grades.

The review was prompted by a federal law called the Every Student Succeeds Act.

White hopes the changes win federal approval in time for them to take effect for the 2017-18 school year.

The state Board of Elementary and Secondary Education plans to hold a special meeting next month to finalize the state's plan.

The deadline for submission to the U. S. Department of Education is April 3.

LABI is often allied with White in efforts to revamp public schools.

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The same applies to other groups that criticized his plan, including the state branch of Democrats for Education Reform, Associated Professional Educators of Louisiana and Stand for Children.

Brigitte Nieland, who follows public school issues for LABI, said Wednesday boosting school performance results through a significant use of yearly progress points is a mistake.

"It will mask lower achieving performance," Nieland said. 

"I do not believe that calling something what it is not benefits children," she said. "It only benefits the adults and administrators in the schools."

The state currently allows 7 percent of yearly academic gains to be calculated in school performance scores.

However, that only applies to struggling public school students.

Carrie Monica, executive director of Stand for Children, said while there is plenty to like about the state's ESSA plan, the fact that school performance scores would include significant progress points, be set on a curve and and other factors are troubling.

All those ingredients means "it is really difficult to get to a place of providing honest and transparent rules on how schools are doing," she said.

White, through a spokeswoman, declined comment on the criticism from the nine groups.

Superintendents also have problems with White's plan, Hollis Milton, president of the Louisiana Association of Superintendents, said Wednesday in an email.

"The formula creates more volatility and masks true achievement," said Milton, who is superintendent of the West  Feliciana Parish School District.

The issue is on the agenda when the Superintendents' Advisory Council, which advises BESE, meets on Thursday at 9 a.m.

On a related topic, the groups said the state should immediately end the curve system used to allocate letter grades.

That means the distribution of A, B, C, D and F grades does not differ from year to year.

The system, which began for the 2013-14 school year, was supposed to last two years and prevent wholesale drops in grades during the move to tougher standards embodied by Common Core.

"A grading curve is misleading to the public and to parents about schools true performance," according to the statement.

The coalition said it spent over three months and 100 hours reviewing the ESSA.

Follow Will Sentell on Twitter, @WillSentell.