State officials said Thursday that public schools showed remarkable gains this year, with 28 percent rated D and F, down from 36 percent last year.
Another 14 percent were rated A, 29 percent B and 28 percent C.
“The bottom line is this is good news for Louisiana students,” state Superintendent of Education John White said.
The grades are based primarily on test results from the 2012-13 school year.
Some education officials questioned whether the latest changes in the rating formula, including new bonus points for low-achieving students, inflated the results.
The Zachary school system, which is rated A, remains the top-rated in the state and has held that spot for nine years .
It is followed by the Orleans, Ascension and St. Tammany Parish school systems.
The West Feliciana Parish school system is rated seventh and the Central district is ninth.
A total of nine districts got A ratings.
The East Baton Rouge Parish school system got a C, the same as last year.
The results mark the first time that the state used a 150-point scale to rate public schools, and made ACT results — a test of college readiness — a key part of high school scores.
After showing major gains last year, 42 percent of high schools were rated A or B, down from 53 percent for the 2011-12 school year.
White said the results show that 71 percent of students are at or above grade level in math and English in grades 3-8.
He said 60 percent of students scored good and above on end-of-course exams, up from 55 percent last year.
As a result, White said, the number of F-rated schools dropped from 12 percent to 8 percent.
Another 20 percent of public schools are rated D, down from 24 percent last year.
But two officials who rarely agree on public school issues questioned the impact of bonus points, which allows schools to gain up to 10 points for significant gains among low-achieving students.
Scott Richard, executive director of the Louisiana School Boards Association, said that, while his group did not want to diminish this year’s gains, the bonus points “definitely had an impact” on scores.
“The fact that formula adjustments have been constant begs the question to the need for a transparency review, a reliability and validity review of sorts,” he said.
Barry Erwin, president of the Council for a Better Louisiana, said that, under the new rules, schools get points “even if kids are not performing to the level we would like to see.”
Erwin said that, while the overall gains are encouraging, “with transitions there is always a little uncertainty because you are changing.”
The state has 1,315 public schools.
White said that, of 429 that showed gains in their school improvement scores, 242 would have risen under the new or old system.
He said rewarding schools where troubled students make progress is aimed at making sure the state does not lose track of them.
One educator familiar with the calculations said the bonus points can be worth half a letter grade, and could allow schools on the cusp to move up a full letter grade.
Patrice Pujol, president of the Louisiana Association of School Superintendents, praised the scores.
“First of all I think these are tremendous results and show the phenomenal efforts of our educators across the state in improving outcomes for our kids,” said Pujol, who is superintendent of the A-rated Ascension Parish school system.
The letter grades stem from a 2010 state law pushed by Gov. Bobby Jindal.
They are designed to give parents, students and others an easy-to-understand way to measure the quality of public schools.
Steve Monaghan, president of the Louisiana Federation of Teachers, said in a prepared statement that the grades signify little.
“He who controls the formula controls the fate of our public schools,” Monaghan said of White.