Fairfax County's elite Thomas Jefferson High School for Science and Technology dropped from second place to fourth in U.S. News and World Report's annual ranking of the nation's best high schools.

Second place is now occupied by BASIS Tucson, in Tucson, Ariz., a branch of a charter school that also exists in the District, and in third place is the Gwinnett School of Mathematics, Science and Technology, just outside Atlanta.

Fourth place is nothing to scoff at, emphasized Robert Morse, U.S. News' director of data research. All schools ranking in the top 15 received perfect scores for "college readiness," indicating that every student has passed at least one Advanced Placement or International Baccalaureate exam, earning college credit.

The top five
1. School for the Talented and Gifted
2. BASIS Tucson
Tucson, Ariz.
3. Gwinnett School of Mathematics, Science and Technology
Lawrenceville, Ga.
4. Thomas Jefferson High School for Science and Technology
Alexandria, Va.
5. BASIS Scottsdale
Scottsdale, Ariz.

The difference in ranking between Thomas Jefferson -- or "TJ" -- and the other schools came down to a "tie breaker," Morse said. The deciding factor was the number of students who passed Advanced Placement exams as a portion of the total number who took the tests.

Though the average TJ student passed seven AP exams -- the same number as last year -- the other schools' students passed more.

But Principal Evan Glazer said he wouldn't want students to be passing more AP exams.

"We're a science and technology school, as our mission, and not a school for Advanced Placement," he said. "A lot of our students are involved in post-AP courses that require AP as a prerequisite."

Some examples of these "post-AP" courses include organic chemistry, computational physics, electrodynamics, artificial intelligence and multivariable calculus, he said. "Those are courses that are still college level but are not accounted for in the U.S. News high school rankings."

So does Thomas Jefferson want to raise its ranking? Not if it means reducing students' abilities to do this "superadvanced research," Glazer said.

But, he added, if U.S. News were to weigh schools' average AP scores across all students, "you would see that our students perform significantly higher." TJ's average AP score is 4.5 out of a possible 5.