Schools are supposed to be the great equalizers. Yet it is far too difficult to tell which cities or states do the most to ensure that all children receive equitable access to strong public schools.

That’s why Education Cities, in partnership with GreatSchools, is proud to announce today’s launch of the first national comparative measure of the achievement gap between students from low-income families and their more advantaged peers.

The Education Equality Index is powered by what we believe is the largest collection of income-focused student proficiency data ever gathered. The data span forty-two states, fifteen thousand cities, seventy-eight thousand schools, and forty-three million children.

With these data in hand, we developed a methodology to measure and compare schools, cities, and states. At each level, we measure the gap between the proportion of students from low-income families who are proficient on a state assessment and the proportion of all students across the state who are proficient on the same assessment. 

We are not measuring within-school or within-city achievement gaps; we are comparing the performance of students from low-income families at the school level to the average performance of all students at the state level. We then assign each school a score that places it in one of four categories, allowing for national comparison. School scores roll up to city scores, and city scores roll up to state scores.

Using this new comparative measure of equality, we have found reasons for both frustration and hope in our first wave of research.

We should be frustrated that only two of ten students from low-income families attend a gap-closing school—and that the majority of large U.S. cities can boast fewer than ten such schools.

But there is also cause for hope: According to the index, there are hundreds of high-poverty schools in the nation’s biggest cities where students from low-income families have closed the achievement gap. These schools prove that you don’t have to look to Singapore or Finland for examples of educational success.

The Education Equality Index brings with it new research opportunities. We can code by school type, school size, free or reduced-price lunch percentage, and geographic location. We are excited to partner with other organizations to explore how states, cities, and schools are closing the achievement gap, and why some succeed while others struggle.

Of course, there are limitations to any research based on student test scores. We know that test scores (and especially proficiency rates) are, on average, strongly correlated with socioeconomic status. And there are many factors, both in-school and out-of-school, that contribute to student success.

But if we want our country to live up to its founding creed, we need to help children from low-income families make dramatic progress. We need schools that overcome the odds. They exist—and we should identify them, celebrate them, and learn from them.

Education leaders in cities across the country should ask: What is happening in the gap-closing schools in my city? What are the conditions that enable these schools to succeed? How can we create those conditions in more schools?

Lastly, the Education Equality Index is an important new factor in our renewed national debate about school accountability in the era of ESSA. We hope this tool will impact the design of new accountability systems, ensuring more emphasis on equitably serving students from low-income families.

To learn more about the Education Equality Index (including our methodology), to see our ranking of the largest hundred cities in the United States, or to see our list of top gap-closing schools in those hundred cities, please visit

Ethan Gray is the founder and CEO of Education Cities.

Policy Priority: