If the state had issued letter grades for nearly 1,300 public schools last year, nearly half would have gotten a “D” or an “F,” according to the state Department of Education.

Whether the picture will be any brighter this year remains unclear on the eve of Louisiana’s first such report card.

Scott Norton, assistant state superintendent, spelled out the history, methodology and other details on the grades in an unusual conference call with reporters on Monday.

Norton declined to comment on how he expects schools to fare under a grading system that is causing nervousness among public school superintendents, principals and others.

The grades will be issued no earlier than Wednesday, said Rene Greer, director of communications for the department.

State officials said in June that, if the grading policy had been in effect in 2010, 46 percent of public schools would have gotten a “D” or an “F.”

In fact, more schools would have gotten an “F” — 81 — than an “A” — 75, according to state figures.

The grades will be linked to annual school performance scores, which primarily reflect how elementary and middle school students fared on key tests.

The scores for high school students are mostly linked to key tests — 70 percent — as well as graduation rates — 30 percent.

The top score is about 200.

Schools with scores of 120 and up earn an “A.”

Those with scores of 64.9 and below get an “F.”

The grading scale was approved by the state Board of Elementary and Secondary Education in December amid controversy.

It gets tougher next year.

Under previous rules, the state used stars and labels to rate public schools.

The letter grades stem from a 2010 law aimed at making school performance ratings transparent for students, parents and other taxpayers.

“Hopefully this will be more meaningful,” Norton said.

Schools that meet annual state improvement targets will get a “plus” on the grade.

Those whose scores drop will get a “minus.”

Schools whose scores rise but fall short of the state target will get a grade only.

School districts will also get letter grades, which include a compilation of student test scores, dropout and attendance rates and other factors.

In addition, school report cards will spell out the percentage of students performing at or above grade level.

The reports also will detail the school’s percentage of minorities, the percentage of students who qualify for free or reduced-price lunches and whether the school is a selective admission site.