Louisiana's controversial plan to revamp its public schools has won federal approval, officials said Tuesday.

The changes were sparked by the 2015 federal Every Student Succeeds Act, which largely required states to come up with new policies to help struggling students.

The blueprint was submitted to the U.S. Department of Education in April after more than a year of arguments, and a six-hour meeting of the state Board of Elementary and Secondary Education in March.

"The U.S. Department of Education's approval of Louisiana's plan is another step in a long process of collaboration and hard work by thousands of Louisianans," state Superintendent of Education John White said in a statement.

The issue put White and self-styled school reformers on one side and Gov. John Bel Edwards, teacher unions and local superintendents on the other, with the governor and others calling for more work and a September submission, not April.

One of the key policy revisions will change the way public school letter grades are calculated.

Under the new rules, yearly academic growth will account for 25 percent of a school's letter grade. Under current rules, those gains make up 7 percent of all-important school performance scores, and they only apply to struggling students.

The state's outline also calls for reduced testing and greater use of federal dollars for troubled schools in rural areas.

In their approval announcement, federal officials praised state plans to gradually raise academic proficiency requirements by 2025, continued school choice options for students in F-rated schools and statewide funding of mentors for aspiring teachers in year-long residencies.

"In reviewing both of these plans, I was glad to see that each state took the opportunity to embrace the flexibility afforded under ESSA while complying with the statute of the law," U.S. Department of Education Secretary Betsy DeVos said in a statement.

Louisiana and Connecticut both had plans approved on Tuesday. They are the fifth and sixth states to win federal clearance.

A total of 16 states and the District of Columbia submitted plans by the first deadline, which was April 3.

The changes take effect for the 2017-18 school year.

Federal approval was not a surprise.

Three independent groups had praised the proposal, and state officials were encouraged earlier this year when questions from federal officials focused on mundane topics.

Edwards and other critics wanted a bigger reduction in state testing, major changes in how public school teachers are evaluated and five more months of discussions.

A total of 61 of 69 superintendents favored sending the proposal to Washington in September.

Other critics included the Louisiana Federation of Teachers and the Louisiana School Boards Association.

BESE in March approved the proposal 7-4, with all three of the governor's appointees casting "no" votes as well as Kathy Edmonston, who lives in Gonzales.

Edwards' office on Tuesday did not respond to a request for comment.

In his statement, White called federal approval a starting point.

"This plan calls for improvement for a generation of school children," White said. "It's time to get to work on making that improvement happen."

The state Department of Education said the plan stemmed from more than a year of talks with educators, parents and community leaders.

The state held 136 public meetings, collected comments from more than 200 groups and over 1,000 individuals.

BESE President Gary Jones also praised Tuesday's announcement.

"While much work lies ahead, Louisiana remains solidly on track to fulfilling its objectives of strengthening accountability, supporting schools and improving educational opportunities for all Louisiana students," Jones said.

The federal action came in the midst of BESE's August committee meetings.

A BESE committee on Tuesday signed off on proposed rules needed to carry out the ESSA changes.

Final votes on the regulations are set for later this year, and could spark more arguments.

Training for supervisors and teacher leaders is also in the works.

On Wednesday the state board will conduct its annual evaluation of White, who has been superintendent since 2012.

Follow Will Sentell on Twitter, @WillSentell.