A new elementary report card in Alexandria public schools that abandons letter grades is causing confusion and concern among teachers and parents who are trying to understand how to reward or encourage academic success in a world without A’s.

The new system measures performance on a long list of specific academic standards using a scale of 1 to 4 — developing, basic, proficient or advanced. Officials have cautioned parents not to equate the numbers with letter grades and have said that the target score is proficiency, or a 3.

But many parents at a PTA meeting Wednesday morning at Lyles-Crouch Traditional Academy in Old Town said they want more clarity on how their children can earn top marks.

“The way it’s been presented, we are striving for average,” said Mary Ritley-White, a parent with a first-grader and a rising kindergartner at Lyles-Crouch. “We want to know how to help our kids strive for excellence.”

The new report cards are tied to more-rigorous academic state standards and intended to give much more detailed feedback about students’ skills and struggles. Rather than assigning a letter grade in reading, for example, teachers provide details about how a student is decoding or comprehending the material.

That feedback helps parents and teachers work with the child to improve, educators say.

“It’s amazing how well kids do at hitting the target, when they know what it is,” said GwenCarol Holmes, chief academic officer for the city public schools.

The standards-based approach to report cards is taking hold across the country, particularly for young children.

Elementary schools in Fairfax, Arlington and Montgomery counties have already made the shift. In Alexandria, kindergarten students are being evaluated with a standards-based progress report.

A task force representing teachers from every elementary school in Alexandria developed the report card over 18 months. The group conducted field tests and surveyed parents, but many parents at the meeting said they had not heard about the new report card until this school year.

The shift is also dramatic for teachers, who have to learn how to grade their students in a new way, one that is much more intensive.

“Right now, it feels like we have our shoes on the wrong feet,” Nancy Pasfield, Lyles-Crouch’s assistant principal, told parents.

The new report card will be customized for each student’s reading and math levels to measure how well they are meeting the standards for those levels, even if they are two years above or below their grade level.

At the meeting, parents puzzled over how students performing below grade level or above grade level could possibly get the same numerical marks. They also asked how there could be an honor roll without grade-point averages and whether admissions offices in private middle schools can interpret the results.

Many parents said they did not understand why the city was not setting higher goals for performance and making it more clear what excellence looks like.

According to the city’s new rubric, the “advanced” rating is supposed to be reserved for students who demonstrate “advanced understanding of key knowledge and skills, consistently applying them independently and creatively.”

But Pasfield said that teachers are still trying to crystallize the difference between a 3 and a 4.

Interim Superintendent Alvin Crawley, who attended the meeting, said he agreed that there should be “illustrative examples of what a 4 is.” He asked parents to continue providing feedback.

“We will keep working on this,” he said.