The Hechinger Report is a national nonprofit newsroom that reports on one topic: education. Sign up for our weekly newsletters to get stories like this delivered directly to your inbox. Consider supporting our stories and becoming a member today.

America faces a tough challenge. Educating students in poverty requires considerably more time than the traditional school calendar offers.

But there’s hope. Expanded time and learning schools are meeting the needs of kids in high poverty schools. These students are getting 2.2 more years of learning across their K-12 education. That’s why we need of to give them this option through all of these years of their education.

The number of expanded-time schools across the country has doubled in the past two years, as my organization, National Center on Time & Learning and the Education Commission of the States reported last week in our 2015 Learning Time in America snapshot of public school time. The increase means over one million students now have access to needed additional hours.

Meanwhile, an ever-growing number of practitioners and policymakers have come to understand how the conventional American school calendar can impede education. In 2014 alone, at least 35 districts across more than ten states announced that they are implementing or considering extending learning time in at least some schools.

Related: Are the Common Core tests turning out to be a big success or a resounding failure?

One of the most significant demonstrations of commitment is New York’s Extended Learning Time Initiative, a $24 million program to lengthen the school schedule by at least 300 hours annually in selected districts. This state initiative is modeled, in large part, after the one in Massachusetts, which saw its first cohort of schools convert to a longer day in 2006. In June, 2014, the New York state education department awarded extended learning grants to nine districts.

The largest state-level project to add learning time in schools is taking place in Florida. Two years ago, the state’s legislature appropriated $15 million in funding to provide the 100 lowest-scoring elementary schools in the state with an additional daily hour of literacy instruction to all students. In 2014, the state legislature allocated $75 million and extended the initiative to Florida’s 300 lowest-performing elementary schools.

Nationwide, expanded-time district schools now outnumber expanded-time charter schools 61 percent to 39 percent. Just five years ago, district schools represented about a quarter (26 percent) of the field of expanded-time schools. Charter schools may have been the pioneers in this movement, but increasingly districts are finding ways to enact this reform.

National Time & Learning’s core philosophy still rings true from its roots 10 years ago: In schools, learning should be the constant, and time must vary to serve the individual needs of students in achieving high standards. National Time & Learning’s funders include the Carnegie Corporation of New York and the W.K. Kellogg Foundation. The Hechinger Report also counts these two foundations among its many funders.

Related: A taste of victory, finally, for a struggling Newark school

There’s still a great deal of work ahead, particularly for high-poverty students. Hechinger recently reported that by the time a child from a low-income family reaches sixth grade, he or she has spent an estimated 6,000 fewer hours learning than a peer from a wealthy household.

High-poverty students benefit the most from expanded learning time. These students often do not have access to the same kind of out-of-school family and community learning resources as their higher-income counterparts. And that’s a reality that widens both opportunity and achievement gaps.

To begin to address these disparities, it is incumbent upon schools to offer more and better in-school learning and enrichment time, so that high-needs students gain access to the additional educational opportunities and individualized supports that flourish in a well-designed, high-quality, expanded-time school.

Policymakers should also integrate expanded learning time into a more comprehensive reform strategy, highlight what works, and add policy incentives.

Equal education opportunity for all has long been a goal for our country. While we have made considerable progress in that direction, a troubling achievement gap still means that students from poverty lag behind their more affluent peers, simply because their school experience is insufficient to narrow the differences in their learning opportunities. Expanding learning time in school is a vital piece of the puzzle, one which helps to build the foundation that will enable the students of today to become the leaders of tomorrow.

By continuing to incorporate expanded learning time into our strategies to improve schools serving our neediest children, we can bring ourselves one step closer to closing the gap permanently.

Jennifer Davis is co-founder and President of the National Center on Time & Learning and previously served as a deputy assistant secretary of education in the Clinton administration.

This story was produced by The Hechinger Report, a nonprofit, independent news website focused on inequality and innovation in education. Read more about expanded learning time.

The Hechinger Report provides in-depth, fact-based, unbiased reporting on education that is free to all readers. But that doesn't mean it's free to produce. Our work keeps educators and the public informed about pressing issues at schools and on campuses throughout the country. We tell the whole story, even when the details are inconvenient. Help us keep doing that.

Join us today.