Are Denver’s nationally-known school reforms paying off? New report says yes.

Top-to-bottom efforts to reform Denver Public Schools are showing positive results, helping the district post the second highest rates of academic growth among large U.S. districts, a new report says.

The mostly laudatory report from Education Resource Strategies, a Massachusetts-based nonprofit, also noted continual challenges facing the 92,000-student district, including widening achievement gaps separating students living in poverty from their better-off peers.

Between 2009 and 2013, DPS trailed only Lincoln, Neb., in academic growth among U.S. districts with more than 25,000 students, the report said, citing federal data. Across all grades and subjects, DPS performance improved almost an entire grade level, the report said.

Academic proficiency increased across all groups of students, and in both district-run and charter schools, it said. The report credited DPS for how it manages schools with different governance structures, saying DPS has avoided “the unplanned under-enrollment and performance degradation in district schools that too often accompanies charter growth.”

However, the report also notes that DPS has taken steps backward in trying to achieve its goal of having 80 percent of students in high-quality classrooms by 2020. For DPS, high quality means schools that rank “blue” or “green” on its color-coded performance system.

As of 2013, DPS was on track to achieve its goals, with 60 percent of students in high-quality seats. That has since dropped below 50 percent, in part because of a shift to new state tests and changes to DPS’s rating formula, the report says.

The report said DPS’s goal may need “recalibration” as a result. DPS Superintendent Tom Boasberg recently told Chalkbeat he still thinks the 80 percent goal is achievable.

Karen Baroody, managing director of Education Resource Strategies, said the organization has worked with DPS in the past and approached the district about the study because it has “systematically tried to retool every part of its system” and seen results.

DPS cooperated with the report but did not commission it, a district spokeswoman said. The work was funded by the Charles and Lynn Schusterman Foundation.

Baroody said Denver’s changing demographics cannot explain the uptick in academic growth since 2009, saying the trend of more affluent families moving in has grown more pronounced more recently.

To better serve high-needs students, the group urged DPS to strategically place “proven models and operators” of schools and adopt policies “that encourage integration in gentrifying neighborhoods.” Baroody said district-run schools that are growing increasingly white and middle class could adopt preferences for higher-needs students much like charter operators do.

Speaking broadly of integration efforts, she said, “I don’t think anyone in the country has figured out how to do this.”

The report also credited DPS for its “willingness to put teeth into accountability systems by closing chronically underperforming schools.” However, considerable effort should be invested in helping struggling schools, Baroody said.

“In reality, you don’t want to keep closing and opening schools,” she said. “It’s like hiring a teacher and saying if they’re great, great, and if they aren’t, fire them. But brand-new teachers need help and support to get better and most schools, if given the right support, will get better.”

District critics will take issue with many of the report’s findings. For example, the report says DPS investment in changing how it evaluates teachers and school leaders “seems to be paying off.” It cites increased rigor in teacher evaluation and high retention of strong performers coupled with relatively higher attrition of low performers.

In the ongoing election for leadership of the Denver teachers union, the teacher evaluation system, known as LEAP, has come under heavy criticism.

Read the full report here.