Schools Chancellor Kaya Henderson opposes a Common Core test switch. (Marvin Joseph/Washington Post)

The District is slated to begin administering new tests next year that aim to gauge students’ performance on the Common Core State Standards, new national academic guidelines that are designed to promote critical thinking instead of rote memorization.

It will be an enormous shift in states across the country, one that likely will have far-reaching reverberations at a time when tests and test scores not only drive instruction in the classroom but also play a key role in determining how teachers and principals are judged and whether schools are considered successes or failures.

Now, on the cusp of that change, some D.C. education leaders are pressing city officials to study whether the District has chosen the right Common Core test or should switch to a different one.

“There’s some concern about, are we doing this right?” said Anne Herr of the Friends of Choice in Urban Schools, an advocacy group for charter schools, whose leaders have been particularly vocal about pressing for information about the coming shift. “It’s a big investment, it’s a big change, and we don’t want to have to do it twice.”

Four years ago, states formed two groups to develop new Common Core tests: the Partnership for Assessment of Readiness for College and Careers, or PARCC, and the Smarter Balanced Assessment Consortium. The District is committed to PARCC.

When the District chose that test in 2010, little was known about the two approaches or how they would differ. Questions still remain, but proponents of switching to Smarter Balanced tests argue that they offer a number of advantages, including shorter testing time for students and a more precise measurement of achievement.

PARCC officials disagree. But the Office of the State Superintendent of Education, the agency responsible for administering city tests, has appeared open to switching, holding February meetings with school leaders to float the issue. The behind-the-scenes discussions were first reported by the blog Greater Greater Education.

Schools Chancellor Kaya Henderson opposes a switch, arguing that teachers unions would see it as an opening to attack the Common Core and testing in general. She also said her team would have to scrap preparations for a test they have long been expecting. City students are slated to field-test PARCC exams this spring.

“Let’s be frank: DCPS is never ahead of the curve,” Henderson told the D.C. Council last week. “This go-round, we actually finally did something right in preparation for something that is coming. . . . So to decide in a couple of weeks that we would potentially undo the preparation we have done causes us to ask, what changed?”

OSSE officials initially said they would decide whether to formally reopen the testing decision by March 3. Now, after gathering feedback from school leaders and national experts, they say they can’t specify a target date but hope to make an announcement soon.

“We believe that the reasons for switching must be incredibly compelling, given the significant potential disruption that a switch at this point would cause,” OSSE spokeswoman Ayan Islam said.

Both tests will be much more difficult than the tests D.C. students are accustomed to, and both will ask students to write essays and short answers in addition to answering multiple-choice questions.

Both also will be administered on computers, but they differ in an important way: Like current standardized tests, PARCC tests will be “fixed form,” which means students at each grade level will take the same exam as their peers, with a mix of questions from easy to difficult.

Smarter Balanced tests will be adaptive, which means the computer will adjust the difficulty of questions depending on each student’s abilities. Get a lot of questions wrong, and the questions will get easier; get a lot correct, and the questions will get more difficult.

Adaptive tests can offer a more precise reading of what students actually know and can do, experts say. That can hold especially true for students working behind or ahead of grade level, for whom the fixed-form test can either be inaccessibly difficult or far too easy.

That’s a powerful idea in a city like Washington, where many children are so far behind that a grade-level test doesn’t say much about what they have learned during the academic year and what they still need to be taught. Students who enter ninth grade at a fourth-grade reading level, for example, could make two or three years’ worth of progress but would still fail a ninth-grade test.

“To assess them on high school work is as close to foolish as anything, because you’re only saying, ‘Well, they don’t know,’ ” said Donald Hense, who leads the Friendship Public Charter School network and supports shifting to Smarter Balanced.

But Smarter Balanced tests likely will only be able to accurately measure performance of those students working within approximately one year above or below grade level, according to Jacqueline King, an official at the Smarter Balanced consortium.

Jeff Nellhaus, director of policy, research and design at PARCC, said PARCC states made a deliberate decision not to use an adaptive test because of concerns about equity: They were afraid an adaptive test would cause teachers to lower expectations for struggling students because they knew those students wouldn’t have to answer hard questions on the end-of-year test.

“The idea of equity became very important,” Nellhaus said. “The idea is that this test would challenge all students in the same way.”

Smarter Balanced also is attractive to some advocates who argue that it will better measure progress that students make each year, rather than simply whether or not they are proficient. That could be an incentive to care about the growth of all students, rather than focusing intently on pushing a few near-proficient students over the line.

But the two tests’ ability to measure growth is far from clear, said Derek Briggs, a professor at the University of Colorado at Boulder who serves on the technical advisory committee for both test consortia.

“So much has yet to be decided,” Briggs said, pointing out that both state consortia are soon conducting wide-scale field tests whose results will determine their abilities to measure growth. “Things are in flux with both of them.”

David Tansey, a math teacher at Dunbar High School, says he believes Smarter Balanced is a step in the right direction. But, he said, tests won’t improve much for students if the city does not figure out how to use test results intelligently. He said that tests are used now to judge schools, but they should be used to map what students know and inform what teachers should teach.

“The onus is still on us,” he said. “If we don’t have a dialogue on what the purpose of all this data is . . . then it doesn’t matter what test we use.”

Irene Holtzman, director of assessments at the KIPP DC charter network, said she favors Smarter Balanced in part because it appears better prepared, having begun field tests last spring, a year ahead of PARCC.

Whatever test OSSE officials choose, Holtzman said, they must solicit and listen to feedback from educators and then be able to explain why their decision is best for D.C. students. “They have this opportunity to stay the course or change the course, but that should be based on evidence and reality,” she said.