As lawmakers look to fix the federal education law mandating standardized tests, a city charter school leader told a group of U.S. senators Tuesday that there is value in testing students throughout the year if the focus is on progress, not just proficiency.

Democracy Prep Public Schools CEO Katie Duffy was one of seven witnesses asked to participate in a roundtable discussion on fixing No Child Left Behind with the Senate Health, Education, Labor and Pensions Committee. Two city teachers testified before the same group of senators less than two weeks ago, but took a more critical stance on testing.

At issue was how the federal government should hold states and schools accountable for student academic performance, since states will likely still be required to administer annual tests and report the results by specific student groups.

During the discussion, Duffy said federal officials should look to Democracy Prep’s model of setting clear expectations for students and letting individual schools meet them “by any means that they deem appropriate.” On a national scale, that would mean setting academic standards and letting states decide how to meet them, she said.

Tests are still a vital component of that model, she noted. Democracy Prep, which operates 10 charter schools in the city, uses a variety of assessments beyond New York’s state tests to measure student progress at multiple points throughout the school year.

“If we just look at an absolute proficiency once a year, we’re not actually going to be able to meet the needs of our kids because we won’t know until June what they didn’t know in January,” Duffy said. “That doesn’t make any sense.”

No Child Left Behind has been criticized for its focus on using state tests to make judgments about student, teacher, school, and districts’ success.

But Duffy noted that the more frequent assessments that the charter-school network finds useful are “not entirely low-stakes.” They are used to decide whether students are promoted to the next grade level and tied to salary decisions for teachers in the network.

While Alexander said the committee is nearing its conclusions on how to renew the law, Duffy urged senators to be mindful of students in urban centers and rural districts still struggling to raise low graduation rates.

We need to ensure “we don’t leave those kids behind because we’re afraid to push forward for accountability and data,” she said.

You can read Duffy’s full written testimony here.