Once a month, Anna Leonhard gets together with nine of her fellow teachers. They work in close collaboration on a variety of activities to strengthen their teaching practice—planning common units, observing each other teach, and analyzing student data. Like many collaborative professional learning situations, these educators teach in the same city (Denver) and focus on the same subject (English language arts or English language development). But unlike most forms of professional development, these 10 educators represent different types of schools: Some are in the Denver Public Schools system and others teach in the city’s public charter schools.

This unique cross-sector learning lab grew out of Denver’s District-Charter Collaboration Compact, which Denver Public Schools Superintendent Tom Boasberg and charter school leaders from around the city co-signed in December 2010. Since then, district schools and charter schools have come together around the shared goal of “improving the ways they work together for the benefit of all students in the city.” In practice, this collaboration has taken several forms, including shared facilities, high-quality programming for special education students, and cross-sector learning labs like the sessions Anna Leonhard attends.

One of the most powerful parts of the common professional development for Leonhard has been hearing her peers’ thoughts on her classroom practice. “I’ve enjoyed sharing what my students are doing and getting my peers’ feedback on what’s going on in my classroom,” she says.

For Leonhard, the monthly cross-sector learning labs also have underscored the value of collaborating with teachers outside of her school—whether they’re across the city or across the country. Since attending a conference with teachers from different states earlier this year, she has kept in touch with fellow attendees online, building a national network of peers that she can tap into for resources and feedback.

As teachers in Denver learn from each other, their students—70 percent of whom are low-income or students of color—are learning, too. In the past decade, Denver’s graduation rate has increased by more than 25 percent. And in the past five years, the percentage of Denver students who scored 21 or higher on the ACT has gone from 16 percent to 24 percent. This progress is a  testament to the amazing things that can happen when teachers and leaders come together and work toward a shared vision of student success.