Many high-achieving students in elementary and middle school don't stay high achievers over time, according to a new study released by the Thomas B. Fordham Institute on Tuesday.

The study, "Do high flyers maintain their altitude," tracked nearly 82,000 students from third grade to eighth grade and more than 43,000 students from sixth to 10th grade. They found that between 30 to 50 percent of students who were initially in the high-achieving group, or who scored in the 90th percentile or above on their state's tests, fell below that threshold over time.

They also found that in reading, low- and middle-achieving students made faster rates of improvement than high achievers did.

"Young people who could go on to be among the highest-achieving kids in the country, go on to help us be internationally competitive, they are falling back down to earth," Michael Petrilli, vice president for National Programs and Policy at the Washington-based Fordham Institute, told Bloomberg. "We are just losing a lot of potential and that's going to hurt us down the road."

One reason for this may be the No Child Left Behind Act's focus on helping the lowest-achieving students, which, researchers wrote in their report, tends to level student achievement instead of enhancing it for all.

"Is helping kids at the bottom improve hurting kids at the top?" Petrilli asked Education Week, adding that the topic may be uncomfortable to discuss but important. "Let's be honest about the trade-offs. It doesn't make you a bad person or a racist."

And the Huffington Post wrote that perhaps there should be an incentive to "to make sure all the kids are making progress" instead of just on closing the gap, or making all students proficient.

Education Week also mentioned that the push for more students, no matter their education record, to take Advanced Placement classes "may have a negative effect on high-achieving students," adding that there has been a "widespread dismantling of policies that group students by ability."

The Deseret News recently explored this debate in an article titled "All for one and one for all: When mainstreaming isn't working."

In the article, researchers discussed how to teach a heterogeneous group of kids in the same classroom by flexibly grouping students by their understanding, yet some believe this is becoming harder to do with large class sizes, demographic shifts and the rigorous passing standards of the No Child Left Behind Act.

"Students who are ahead in a class are sometimes told to silently read or work on their homework while the rest of the class catches up," the paper reported.

"We've been making good progress for kids at the bottom and for poor and minority kids—that's important," Petrilli told Education Week. "It just can't be the only thing that we do."