It’s official: For the first time since letter grades were assigned to Florida’s public schools, not a single traditional high school in Miami-Dade or Broward county received a D or an F grade from the state.

“Both of the districts need to be commended for the way we scored,” said Nathan Balasubramanian, Broward Schools’ executive director for strategy and continuous improvement.

On Friday, the Florida Department of Education released the letter grades, which reflect the 2011-2012 school year.

Miami-Dade Superintendent Alberto Carvalho called the scores “compelling.”

“Last year, we celebrated the fact that, for the first time, all of our high schools earned above an F,” he said. “This year, we celebrate the fact that we have eliminated D-rated high schools.”

About 63 percent of Miami-Dade schools earned an A grade, and 88 percent received an A or B.

There were no Ds or Fs in Broward either, where 69 percent of schools earned an A grade, and 82 percent scored an A or B. Both counties significantly outperformed state averages in the percentage of A’s and B’s awarded.

Broward, Balasubramanian said, will be studying the strategies employed at schools that showed the biggest improvements, with hopes of replicating that success district-wide.

Standardized tests are the biggest driver of Florida’s high school grades, though the state also factors in graduation rates and participation in advanced-placement courses.

One of Broward’s big winners Friday was Hallandale High School, which leaped from a C grade to an A. Hallandale High principal Estella Eckhardt engineered such dramatic progress in only her first year at the school. Eckhardt credited the school’s Saturday tutoring sessions (with hot breakfast and hot lunch), a culture of high expectations, and a push to emphasize reading instruction.

“Everybody teaches reading in my school — everybody,” Eckhardt said. “A band teacher teaches reading...that way, the students are exposed to it.”

Other high schools that jumped from a C to an A included Piper High School in Broward, and American, Miami Norland and Miami Springs in Miami-Dade.

Also performing well was the City of Hialeah Education Academy, a charter school that offers specialized programs in law enforcement, firefighting and emergency response. The school earned its second straight A since opening five years ago.

“We’re so happy,” said Principal Carlos O. Alvarez. “We’re a high-poverty school. Our kids struggle at home. But we’re able to change them and mold them, and really transform their lives.”

Alvarez credited the school’s focus on discipline and character education. He also noted that the teachers analyzed student test performances throughout the year — and shared their findings with students, parents and the school’s governing board.

“The kids really took ownership of their education,” Alvarez said. “They were monitoring their own performance.”

Florida’s school grades are about a lot more than bragging rights. Schools get extra funding (and teachers receive bonuses) as a reward for high grades, while schools that consistently post failing grades can ultimately be forced to close. The reputation associated with a letter grade can also affect a school’s ability to attract new students.