Portland prides itself on its diversity — both in its schools and broader community. Unlike many Maine communities, Portland Public Schools offers the opportunity to learn from and grow with students from diverse backgrounds. Unfortunately, this diversity often ends at the school entrance.

I have observed in classrooms throughout the city’s public schools for the last decade. My Bowdoin College students learn to teach in Portland’s schools. I volunteer weekly in my child’s elementary school. I am proud that several Bowdoin Teacher Scholars are employed by Portland Public Schools. Yet, too often to document, I have sat in a high school classroom surrounded by students of color. The bell rings and a new set of students takes their seats, most of them white. I am told that the first is a lower-track class and the second is a higher-track class.

Also known as “ability grouping,” tracking is prevalent across Maine schools and throughout the country. This practice becomes particularly pronounced in middle and high schools as students are separated into levels such as honors courses, general courses and college prep courses.

Parents are aware of this phenomenon. When I ask middle-class white families what the diversity is like for their children within the Advanced Placement and honors classes, their discomfort is palpable. Or, my question may elicit explanations that veer dangerously close to the race- and class-based assumptions that supported the eugenics movement.

Many of my white, middle-class neighbors also are proud of Portland Public Schools. They detail the variety of AP courses offered in their schools. These same families also will remark how grateful they are that their children go to a school with such diversity, especially in a state as white as Maine.

Portland’s schools fall short of offering equitable educational opportunities to all students. But our city’s commitment to diversity, not to mention U.S. law, requires that we examine and alter the practice of tracking in our schools.

My neighbors who are people of color and/or multilingual are frustrated by unequal outcomes, especially within the high schools. The most recent Portland Public Schools district scorecard reveals striking disparities based on race and family income. For high school students, the SAT serves as the state’s measure of high school proficiency. More importantly, SAT performance indicates likelihood of college enrollment.

Only 14 percent of black students in the 11th grade met proficiency benchmarks in English language arts in 2014, and only 18 percent met those benchmarks in math. Students designated “economically disadvantaged” fared similarly: A mere 19 percent were designated proficient in English and only 23 percent achieved proficiency in math. Meanwhile, more than 50 percent of Portland’s white students met the proficiency benchmarks in both domains.

The names given to the tracks can be misleading. For instance, a parent could reasonably assume the “college prep” track is preparing his or her child to enter college. At many schools, “college prep” is the name for the lowest track — but students in this group often do not take the courses required by many colleges’ admissions criteria.

Research shows that tracking consistently leads to racial, socioeconomic and language-based segregation and unequal outcomes within schools. Nevertheless, tracking persists in many schools across the country.

Administrators and teachers argue it is easier to teach students if they are grouped by their so-called ability. But placement in a track is most often an indicator of a family’s socioeconomic status than a student’s ability. Parents who feel confident in advocating for their children in school settings may intervene and request that their child be placed in a higher track. Test scores that may be used to determine track placement are unreliable predictors of students’ academic potential and engagement. Students who must work or provide child care for their family are may not be able to meet summer requirements for entering a high school honors track, regardless of interest or ability.

Like all families, white, middle-class parents want the best for their children. District and school administrators, eager to keep these students in public schools, often will honor parental placement requests. But parents of color and those from low-income backgrounds may not be aware that the practice of intervening on student placements is standard operating procedure. Even if they do know, they may believe — with depressing accuracy — that their efforts will be ineffective and decide to focus their energy elsewhere. Multilingual families face even greater barriers in advocating for children in their care.

The U.S. Department of Education’s Office of Civil Rights “ensures equal access to educational opportunity” and is taking action in response to complaints of civil rights violations across the country. Tracking is one source of those complaints. For instance, a recent Office of Civil Rights investigation revealed that black students were significantly underrepresented in rigorous courses in the South-Orange/Maplewood, New Jersey, schools.

We learn from the 2016 Office of Civil Rights report that simply offering rigorous classes is not the same as providing equal access to rigorous classes. One of the ways the Office of Civil Rights assesses equal access is by comparing the percentage of the total population of students of color and multilingual students learning English to the population enrolled in rigorous courses.

Documenting the problem is an important first step. The real work begins when we begin to truly diversify all aspects of our schools to provide equitable opportunities for every student.

Doris Santoro is associate professor and chair of education at Bowdoin College. She lives in Portland, and her daughter attends a Portland Public School.