The U.S. Department of Education is doing away with a policy that allowed states to consider some students with disabilities academically proficient without meeting grade-level standards.

The agency said in a final rule published late last week in the Federal Register that states will no longer be allowed to administer tests to students with disabilities that are based on modified academic achievement standards.

Previously, states could count up to 2 percent of their students as proficient under the No Child Left Behind Act for taking such exams. But now the Education Department is saying no more to the policy known as the “2 percent rule.”

“We believe that the removal of the authority for states to define modified academic achievement standards and to administer assessments based on those standards is necessary to ensure that students with disabilities are held to the same high standards as their non-disabled peers,” the agency said in the rule, which will officially take effect Sept. 21.

The move is designed to ensure that students with disabilities who are capable of meeting general education standards with proper supports are not shortchanged, the Education Department said. Any state still using modified standards and assessments will have one year to phase them out.

Despite the change, children with the most significant cognitive disabilities — as many as 1 percent of all students — will still be allowed to take tests based on “alternate academic achievement standards” under the rule.

The shift away from modified assessments has been in the works for several years. U.S. Secretary of Education Arne Duncan pledged in 2011 to move away from the 2 percent rule. And, his agency formally proposed the change in 2013.

In issuing the regulations, the Education Department cited new research showing that students with disabilities who struggle with reading and math can achieve at grade-level standards if provided “appropriate instruction, services and supports.” What’s more, the agency said that nearly all states have new standardized tests “designed to facilitate the valid, reliable and fair assessment of most students, including students with disabilities who previously took an alternate assessment based on modified academic achievement standards.”

Nearly every state has already transitioned away from administering modified assessments, according to Lindsay Jones, director of public policy and advocacy at the National Center for Learning Disabilities.

“The department’s final rule meets a commitment it set for itself and really recognizes what we know to be true — we don’t need loopholes, we need to focus our efforts on supporting teachers to provide the best instruction they can to students with disabilities,” Jones said.