There won’t be any more straight-A students next year in Fairfax County elementary schools. Thanks to a bold change in grading policy, there won’t be any more A’s at all — or, for that matter, B’s, C’s or D’s.

The letter grades stamped on report cards across America, long symbols of academic success or failure, are vanishing from many schools in the Washington area and beyond.

For years, anxiety and ambition have hung on the letters, but educators now say that the metric is imprecise and does little to reflect a student’s progress, especially in the early years of schooling.

In Fairfax, officials will soon implement a detailed report card that instead uses numeric values from one through four and adds dozens of new categories in which progress will be measured. One Arlington County school has replaced report cards with a long-form narrative, without boiling down the evaluation to numbers or letters.

“This is a huge change of culture,” said Judy Heard, a manager in Fairfax’s instructional services department. “Letter grades have predominated for a long time, but they’ve rarely been well-defined. It’s time for a new approach.”

Not all educators agree. Montgomery County experimented with numerical report cards but backed away from the model after encountering opposition from parents. Prince George’s County schools also tried the numerical model but reversed course, a spokesman said.

Still, public elementary schools in the District moved away from letter grades two years ago. Other school systems, including Alexandria’s, are likely to adopt the new metric but are still finalizing the details.

Schools from New York to California already use similar reports, but Fairfax is among the largest systems to make the change: 40,000 of its students who now receive letter grades will soon bring home numerical report cards.

The new approach marks an attempt to incorporate instructional standards — crafted in recent years by local and state agencies — into the grading process, focusing on a student’s development in more than 50 detailed skill areas. For example, rather than receiving a single grade in math, students will be judged on the one-to-four scale in seven math-related fields, such as computation and measuring.

The new metric marks a significant departure from traditional report cards, which often measure a student’s achievement relative to the rest of the class and do little to break down strengths and weaknesses within a given subject area. But it also means that the bumper-sticker-ready title of an “A” student will in many places become a superlative of the past, replaced with helpful, if clunky, nuance.

Some parents prefer the power of letters.

The new report cards “don’t provide any recognition for a child who is consistently doing excellent work and exceeding the standards,” said Grace Becker, a Fairfax parent who participated in a focus group last year. “We knew what an ‘A’ meant. We knew what a ‘B’ meant. But the new system can be very confusing.”

Letter grades remain the standard for middle and high schools nationwide, in part because of the importance of grade-point averages in college admissions.

At the elementary level, the new report cards emphasize social and emotional growth — developmental concerns often ignored by conventional report cards but of growing interest to educators who say traits like curiosity and cooperation serve as predictors of long-term academic and professional success.

The so-called standards-based rubric has been rolled out in 10 Fairfax schools over the past year. Next fall, every remaining Fairfax class from kindergarten through sixth grade will follow suit. In those schools, the top grade will be a 4, indicating that the student consistently demonstrates concepts and skills in a particular field. There will be no mention of whether a student’s performance is above or below average. There’s also no failing grade.

“It took some time for us to understand what each standard meant, but now it gives us a chance to communicate what we’re actually doing in the classroom. Letter grades didn’t do that,” said Katherine Booth, a fourth-grade teacher at Sunrise Valley Elementary in Reston, which introduced the new progress reports last year.

Educators say the shift toward the new report card is substantive. But it also sends a message to parents that in key developmental years, a report card should mark more than the threshold between success and failure in basic subject areas. They say it should also highlight the wide range of skills a student — whether identified as remedial or gifted — will need to succeed beyond elementary school. Most schools traditionally offered satisfactory and unsatisfactory marks for kindergarten through second grade and letters A through D in the higher elementary grades, often assigning other letters to those who fail.

As a growing number of schools moves away from letter grades, they’re seeking a host of alternatives. While Fairfax administrators last school year approved the numerical approach, at least one Arlington school is offering a “narrative” report card, with a smattering of student work samples and instructional analyses delivered to parents.

In June, teachers at Campbell Elementary School explained the method to parents, a glimpse into the world of report cards without letter grades.

Jose Machado learned that his 7-year-old daughter, Jennifer, was gifted at decoding big words. He learned that she was particularly enthusiastic about science, that her spoken English still needed work (the family is from Bolivia) and that her best friend’s name is Emily.

But when the teacher, Pat Findikoglu, finished her explanation, Machado paused. At that point, a parent might have asked about letter grades. But here, there were none. Instead, Machado asked a few questions about summer school, and the two shook hands. In large part, the conversation itself was the report card.

“The approach doesn’t make the student smarter, but it makes the teacher better,” said Sam Meisels, who pioneered the narrative report card used at Campbell, which is distributed by Pearson Education. “A letter grade is a short-lived triumph. . . . It doesn’t tell us what we need to know about a student’s progress.”

Staff writer Bill Turque contributed to this report.