Sign up for Chalkbeat’s free weekly newsletter to keep up with how education is changing across the U.S.Knox County Schools looked like it was doing everything right. The district was using a well-regarded, evidence-based curriculum to teach students how to read. Young students who struggled got intensive tutoring using high-quality supplemental materials. Tutoring sessions took place during the school day, ensuring high participation.But the 60,000-student district in eastern Tennessee wasn’t seeing the results from tutoring that leaders had hoped for. Erin Phillips, the district’s executive director of learning and literacy, decided to try something new: ask tutors to use materials that matched what students were learning in the classroom.Working with outside researchers during the 2024-25 school year, Knox County Schools randomly assigned more than 300 early elementary students who fell below the 40th percentile on a universal literacy screener into two groups. One group received tutoring using the district’s usual supplemental materials. The other got tutoring using materials that were aligned with the district’s core curriculum, Benchmark Advance. The results, described in a paper by researchers Cara Jackson and Ayman Shakeel, were striking. Students who received tutoring that aligned with classroom instruction made more progress, the equivalent of an additional 1.3 months of learning, compared with students in the control group whose tutoring sessions used supplemental materials. This approach and the outcome might sound like common sense. But it goes against a widespread way of thinking about intervention, that if students didn’t learn the material well in class, they might benefit from new ways of approaching it or different explanations of the same concepts. But the study suggests the opposite was true, that teachers and tutors may have inadvertently confused students by, for example, teaching different letter sounds in different orders or referring to the “magic e” in one setting and the “silent e” in another.The findings are important as school districts look for ways to make tutoring more effective with limited dollars. School districts were urged by experts and officials to invest in high-intensity or high-dosage tutoring, generally defined as occurring at least three times a week and for 10 weeks or longer, as an evidence-based way to address pandemic-related learning loss. But large-scale tutoring programs often failed to produce the same outcomes as carefully designed pilot programs.The education sector jargon for what Knox County is doing is “coherence.” That’s simultaneously an increasingly popular buzzword and a vital missing element in many education reforms. In Knox County’s case, “What we were asking our most at-risk learners to do is carry the heaviest cognitive load,” Phillips said. “We were calling the same thing by different names in every learning experience. We were overloading their ability not only to have that knowledge in their brain, but to retrieve that information, not only retrieve it, but then apply it, and then transfer it from place to place.”Using aligned materials, in contrast, lightens their cognitive load and gives them more opportunity to practice the same skills covered in class, she said.Knox County students using aligned materials also did better on state standardized tests, according to the study from Jackson and Shakeel, though the difference was not statistically significant.Tennessee is in its fifth year of a major early literacy initiative that includes teacher training, state-approved curriculum lists, mandatory tutoring for certain students, and holding back students who don’t meet certain benchmarks by third grade. Stanford University’s National Student Support Accelerator’s review of tutoring research notes that alignment seems like it would be good practice but doesn’t have a strong research base. Jackson, research manager at the Center for Outcomes Based Contracting, said she wanted to address that gap with a randomized controlled trial. “We were testing something lots of people very much believed would be true, and that a lot of people have talked about for a long time,” she said. Jackson said she hopes other researchers try to replicate her findings in other settings and with larger groups of students. Phillips is moving to adopt more aligned curriculums across subjects and grades. She’s also continuing to closely monitor student learning, including whether fewer students score in the bottom quartile or are referred for special education evaluation. She said the study results shed light on a long-standing problem in the district.“We had a decade’s worth of data showing us that students were not exiting intervention,” she said. “They were becoming intervention lifers. That’s not the intention of this support. All this data was showing that this was not working.”Different curriculum choices can create an unhelpful ‘lasagna’Many factors have nudged districts away from using aligned curriculum for students in intervention services, according to TNTP, a school improvement consulting organization that worked with Knox County. Large established publishing houses dominate the market for core curriculum, while dozens of smaller companies fill in the gaps. When states draw up lists of approved curriculum, core and supplemental materials might go through different approval processes, and districts might not see materials from the same company on both lists. Grants might also require districts to pick materials from certain vendors, contributing to a proliferation of different learning materials that take different tacks.“We build this lasagna of program over program over program,” said Devon Gadow, TNTP’s director of national consulting.Surveys by the research organization Rand Corp. found that teachers frequently cobble together materials from different curriculum companies, with the average teacher reporting they used two core curriculums and five supplemental curriculums. And a study by the Center for Education Market Dynamics found more than 350 different supplemental math products in use across 1,700 school districts. These same school districts chose from fewer than 20 core curriculum options. While districts often put significant time and attention into assessing core curriculum options before making a decision, they adopted supplemental materials in an ad hoc way, in part because the contracts were shorter and less expensive, the analysis found.TNTP is urging state policymakers to look at ways they may be steering districts away from using more-aligned materials. The group also wants district leaders to look at what they already have in their arsenal that they could redeploy. Gadow said district officials should be wary of marketing pitches based on coherence or alignment. They may not need to buy something new as long as they’re already using high-quality materials. Core curriculum often includes materials to support scaffolding, remediation, and intervention, Gadow said, but classroom teachers don’t have the time to read through every page and develop lessons for struggling students. That’s work that central office staff could take on.In Knox County, Phillips said teachers had developed a habit of using supplemental materials in the past when the district’s core curriculum wasn’t as good. Those habits were hard to break, in part because those past experiences led teachers to distrust that any core curriculum could cover all the necessary ground. Phillips spent roughly $1.4 million from what remained of Knox County’s pandemic relief on aligned supplemental materials from Benchmark at the beginning of the study period. But if she had it to do over again, she would have looked more closely at what already existed in the core curriculum, she said. That’s what she’s doing now for other subjects. Most teachers are on board with the change, she said.Meanwhile, she’s phasing out materials from other publishers as licenses expire, saving money going forward.Erica Meltzer is Chalkbeat’s national editor based in Colorado. Contact Erica at emeltzer@chalkbeat.org.