ROCKVILLE, MD. - For years, Rockville High School has sent the children of doctors, lawyers and high-ranking government officials on to top-notch universities.

But for Principal Debra Munk, one story stands out: a black student, a Zambian immigrant, who went on to Harvard University.

It's Nyamagaga "Gaga" Gondwe's humble home life, not her race, that gives Munk cause to celebrate: In this Washington, D.C., suburb where the average home price hovers near $400,0000, Gondwe grew up in public housing.

Gondwe's experience is at the intersection of efforts that have brought praise and pilgrims to Maryland's Montgomery County Public Schools for its work to narrow the achievement gap between white and minority students -- a problem that has plagued Minnesota's schools for decades.

Educators from Osseo to Tochigi, Japan, travel to Rockville to study the school system, exploring everything from its cutting-edge data system to its efforts to pump more money into impoverished schools.

"[Closing the gap] doesn't happen in a year ... it doesn't happen in five years," said Osseo schools Superintendent Kate McGuire, who visited Montgomery County in late January. "This takes a really sustained focus."

Montgomery County built its reputation on its hard sell to minority parents on the benefits of getting involved, frank discussion about the achievement gaps and an intense focus on data -- from test scores to suspension rates.

Problems are diagnosed early and intervention comes quickly. Testing identifies talented non-white students as early as second grade, to prepare them for demanding high school AP and International Baccalaureate classes that can smooth the path to a college degree.

"There's an old adage: What gets measured gets done," said Adrian Talley, an associate superintendent with the district's Office of Shared Accountability. "But as opposed to using [data] as a hammer, we use it to shed light."

In 2010, the district was a finalist for the $1 million Broad Prize, an award honoring urban school systems that improve student performance while closing gaps among low-income and minority students. That same year, a Pew Center on the States report praised Montgomery County as a model for local districts, state education departments and federal policymakers seeking solutions to the education gap.

Yet problems persist. After a decade of reform, the gaps between white and non-white students in the district's middle and high schools haven't narrowed as fast as administrators, teachers or parents would like.

"We're not finished," said school board member Judy Docca, a retired district principal and teacher. "We've made some strides ... but we're still looking for answers."

Growth in diversity

By Minnesota standards, Montgomery County is huge, with more students than Minnesota's five largest districts combined. It has already seen the demographic shifts underway in the Twin Cities area and developed a response to them.

A decade ago, half the students in Montgomery County where white. Today, enrollment is about 37 percent white, a quarter black, a quarter Latino and more than 15 percent Asian.

That shift foreshadows the decades-long changes in the Anoka-Hennepin, St. Paul, Minneapolis and Osseo schools, once majority-white districts that now, combined, have enrollment that is split almost equally between white and non-white students.

When former Superintendent Jerry Weast came to Montgomery County in the late 1990s, he predicted the emergence of a two-tiered school system: a "green zone" that was mostly white and wealthy and a "red zone" with schools that had many poor, mostly black and Latino students.

In the past decade, the number of English language learners in the district's elementary schools has tripled and 44 percent more children are eating free or reduced-cost meals.

To confront the changes, the district created Study Circles, a program to get parents and educators talking about student achievement -- but also race, language barriers, finances and other problems outside the classroom. The sessions have brought teachers and principals closer to a wider range of families.

"Until we have the honest conversations that we need to have how race and ethnicity affects our lives, we can't make progress," said program coordinator John Ledesma.

During Weast's tenure, the district began tracking the percentage of graduates who earned a college degree within six years. Overall, the district's college completion rate is 60 percent. But the rate remains higher for white and Asian students than their black and Latino peers.

"It's a stubborn gap," Munk said. In her seven years at Rockville High, her "extremely pushy" approach to getting black and Latino students into honors classes has propelled the percentage of students taking college entrance exams from 30 to 80 percent.

A visible divide

The success at Rockville High hasn't spread as readily throughout the district's "red zone" schools, despite mandates to spread the wealth.

Montgomery County ranks among the 20 wealthiest counties in the country in household income, but remains plagued by pockets of poverty. More than two of five students have qualified for free or reduced-price lunch, a federal poverty indicator.

What has worked well, some parents and researchers say, is a countywide affordable housing policy that integrates schools without using state or federal education funding.

Though she never personally felt poor among her more affluent classmates, "the socioeconomic disparity in Montgomery County is very visible," Gondwe said.

Students like Gondwe who didn't grow up among the well-heeled but attended schools with more affluent classmates outperformed their peers who didn't, a 2010 study from the Century Foundation found.

Researchers linked the results to three things: engaged students, involved parents and top-notch teachers who are attracted to schools with low-income student bodies.

"I never felt out of place for wanting to be high-achieving," said Gondwe, now a junior at Harvard.

The benefit of integrating Minnesota's schools remains under debate, with state legislators mulling the proper use of more than $100 million in annual desegregation funding that has so far produced inconclusive results.

In Montgomery County, even the district's staunchest critics, the Montgomery County Parents Coalition, say integrating schools has brought academic success, along with a stable teaching staff and steady funding.

With more than a third of her students living in poverty, Wood Middle Principal Jeanie Dawson oversees a building that is a mix of green zone and red zone. Dawson and her staff have the 530 days of middle school to reach their goals: close the gap between the success students have in Montgomery County's elementary schools and what they will experience in high school and beyond.

Like her counterpart at Rockville High, Dawson pushes to get more underrepresented students into advanced classes.

On a recent afternoon, one black student stood out in an honors geometry course.

"If kids are challenged, with support, they rise to the opportunity," Dawson said. "It's about equity, providing opportunities for all students."

Corey Mitchell is a correspondent in the Star Tribune Washington Bureau. Twitter: @StribMitchell