Sign up for Chalkbeat’s free weekly newsletter to keep up with how education is changing across the U.S.The architects of Denver Public Schools’ former reform efforts are lauding a new study that validates a strategy that largely has been abandoned both in Denver and nationwide: closing low-performing schools and opening new ones that might serve students better.The analysis from University of Colorado Denver researchers finds that most students who left closed Denver schools and attended new ones saw their test scores go up, with greater gains for English learners and students with disabilities.Student achievement also went up districtwide, which study authors attribute to years-long efforts to give school leaders more autonomy, hold them accountable for results, and make it easier for families to choose among a range of schools.“Too many school reforms in this country last for a year, and then the next year everybody changes their position based on what happened the year before,” U.S. Sen. Michael Bennet, Denver’s superintendent during the start of the reform era, said during a panel discussion Friday. “Denver, unlike many other places, had a commitment to a complicated and nuanced approach. I hope that people will have the chance to rediscover the work because of this research.”Researchers who reviewed the study at Chalkbeat’s request said it was generally well-designed and makes a strong case that Denver’s approach contributed to improvements in student test scores. However, they cautioned that its boldest claim — that students experienced as much as three school years worth of additional learning — may be overstated.The study adds to an extensive body of research on school closures, some of which has found mixed or negative effects. After years of bipartisan support from policymakers and others, test-based school accountability has mostly fallen out of favor in large urban districts.In addition to the political backlash this approach frequently sparked, improvements stemming from it proved hard to sustain over time. But different approaches to school improvement have been slow to emerge as schools grapple with the pandemic’s effects on student outcomes.Now, many urban districts — including Denver — are facing the prospect of school closures due at least in part to a different factor: declining enrollment. As it prepares to pick which schools will close next year, the Denver school board initially rejected the idea of considering academic performance but now says it can be a factor, just not the sole one.Superintendent Alex Marrero tried to prevent the release of the student data used in the new study, contending that the researchers would ignore the downsides of reform policies and focus too narrowly on test scores. A spokesperson for the district did not respond to a request for comment on the study findings.Denver schools study examines test data, graduation ratesDenver was once seen as a national exemplar of the so-called portfolio model, which encouraged school choice with an easy-to-navigate enrollment system.The district also encouraged new schools to open, including charter schools, which are publicly funded but independently run, and innovation schools, which are district-run schools where principals have additional freedom and flexibility.Simultaneously, the district closed schools with persistently low test scores.Some of the Denver schools that opened during this time period continue to be sought-after and highly regarded schools. But others have closed due to low performance and low enrollment.“It is really this idea that if you embrace the idea that choice is not a threat but an opportunity, if you don’t assume you have all the answers, and you hold schools accountable for results, you will see system-wide improvement,” said Parker Baxter, the study’s lead author and head of the Center for Education Policy Analysis at CU Denver’s School of Public Affairs. “And that is apparently exactly what happened in Denver.”The new study isn’t the first to find that Denver made significant improvements during the reform era. In 2022, Baxter released a study that found that from 2007-2008 to 2018-2019, Denver students made an additional year or more worth of academic progress. Graduation rates also increased at a higher rate than they would have without the reforms, the study found.But critics said that study, which used districtwide test data, didn’t account for the 20,000 new students Denver added during that time who were disproportionately whiter, more affluent, and more likely to do better on standardized tests.The new study draws on test scores and other data from 40,000 individual students from Denver and 11 surrounding districts from the 2008-09 school year to the 2014-15 school year. The Denver students were matched demographically and academically with similar students in neighboring districts that did not embrace the portfolio model. The more time students attended Denver Public Schools, the greater the increase in their test scores compared with similar students, the study found.The study also tracked individual Denver students over time, including those who attended schools that closed, those who attended new schools that opened during the study period, and those who attended schools targeted for district-led turnaround.Most students who left a school that closed due to low performance for a new school that opened during this period saw their scores increase in math. Students who attended a new school saw test scores increase in math and English. One exception was Native American students, who generally saw their scores go down.Students who attended schools in turnaround — an often demoralizing process that involved replacing the principal and many of the teachers — generally did worse.“At least for the students in our sample, the most minimally disruptive interventions had negative effects for students,” Baxter said. “Arguably the most disruptive intervention had the most positive effects. It’s important to understand why.”As the district prepares to close schools again, closing those with lower test scores could be a way to turn the disruption into academic gains, Baxter said.Denver’s high school graduation rates increased dramatically during the time period of the study, but the same held true in many Colorado school districts. Overall, Denver students in the study were a little more likely to graduate high school but not more likely to go to college than their peers in neighboring districts.Hispanic and English learner students in Denver were more likely to go to college than their suburban peers, while Denver’s Black students were less likely to enroll.‘Strong evidence’ reforms were effective, but which reforms?Douglas Harris, an economics professor at Tulane University who has studied school reforms extensively, said the latest study is “more convincing” than the first study that education reform policies influenced Denver student trajectories.The new Denver study produced similar results to Harris’ own research in New Orleans, though students there saw more modest test score growth and greater effects on high school graduation and college-going rates, he said.Rob Shand, an assistant professor of education policy and leadership at American University who wrote a critique of Baxter’s earlier work, said the new study addressed several concerns but may attribute too much of the improvements to reform policies.Shand said the way the study authors added up yearly test score gains to arrive at large cumulative effects “might tend to overinflate the numbers.” Nonetheless, the study provides “strong evidence that the Denver reforms increased test scores quite considerably,” Harris said.Baxter defended the approach and said it may even have underestimated the effects.Baxter said nearly every policy in place in Denver at the time was related to education reform and the portfolio model, including paying teachers more to work in high-poverty schools, giving schools more money to serve students from low-income families, developing a customized school rating system, working closely with charter schools, and making it easy for families to choose among schools. That makes it reasonable to credit test score gains to the portfolio model more broadly, he said.Shand said there’s value in studying comprehensive reforms, but it’s hard to know how to respond because it’s not clear which policies made the most difference. It’s a stretch, he said, to treat every policy as part of the portfolio model, and no community could copy everything Denver did.Still, in a time when education politics is increasingly polarized between defenders of traditional public schools and supporters of universal private school choice, Shand said the study results should give pause to both extremes.“It really calls for a more balanced or measured approach,” he said.At Friday’s panel discussion on the report, Bennet and former Denver Superintendent Tom Boasberg made a rare joint appearance to reflect both on the findings and on a political landscape that has changed a great deal.Opponents of their reforms took control of the school board in 2019 and have been less friendly to charter schools and giving principals autonomy. DPS hasn’t closed a traditional school for low performance since 2016. The school board scrapped Denver’s school rating system in 2020 and hasn’t come up with a replacement.Bennet and Boasberg said the election of Donald Trump in 2016 polarized every area of politics and contributed to the erosion of a bipartisan consensus on education.Boasberg, who now leads an American school in Singapore, said the study represents an opportunity to turn the focus from politics and rhetoric to policy and practice. He acknowledged, though, that the nature of the reforms also contributed to some of the backlash.“These were very, very far reaching changes, and they changed the status quo in very deep and very profound ways,” Boasberg said. “And I think in any democracy, when you make very profound changes that change the status quo, there are people who are going to be unhappy and resist.”Colorado bureau chief Melanie Asmar contributed reporting.Erica Meltzer is Chalkbeat’s national editor based in Colorado. Contact Erica at emeltzer@chalkbeat.org.First published by Chalkbeat.