The problem isn’t just that school systems shuttered by the coronavirus pandemic suddenly face the huge challenge of improvising home-schooling routines on an unimagined scale. Students everywhere lack access to online tools.

Many can’t afford them. And even where poverty isn’t the main barrier, few schools have developed a sophisticated digital capability. The promise of a technology revolution that would customize K-12 education to each student’s needs was sidelined early on by efforts to use technology to undermine unions, replace teachers and increase class size, alienating many educators.

Training has been spotty and has left teachers and administrators unprepared. Scandals have plagued both for-profit online K-12 schools, which consistently underperform their brick-and-mortar counterparts, and for-profit online colleges. Meanwhile, the idea that universities like Harvard and the Massachusetts Institute of Technology could deliver elite instruction to the masses through the massive open online courses dubbed Moocs was undermined by media hype.

Especially for elementary and high schools, where large-scale systematic research on online learning has been sparse, the online-education experiment set off by the coronavirus offers an opportunity — one that won’t be fully realized until the crisis is over — for state and local governments to assess how educators married technology and teaching on the fly. As they invent their virtual classrooms, teachers and districts also have a unique opportunity to document what works and what doesn’t and to seize back the momentum from philanthropy-backed organizations that have sought to redefine public education.

As schools and colleges gather students in virtual meetings using Zoom or Google Classroom, one key obstacle to online education has come into sharp focus: The shortage of computer access and internet connections in high-poverty urban centers such as Miami and Los Angeles, where about 15 percent of students lack computers or internet access, and in rural areas, including vast swaths of the South.

The Los Angeles Unified School District has enough devices for only about two-thirds of K-12 classes, prompting the superintendent to ask the state for $50 million to supply the remaining students with tablets, and local internet providers for free access for L.A.-area families, about one-quarter of whom have no broadband access.

In New York City, an estimated 114,000 children live in unstable housing, including homeless shelters where WiFi is sparse. The education department is expecting to roll out 300,000 internet-enabled iPads, even as some principals emptied their laptop carts so kids could take home devices before schools closed.

Colleges also are wrestling with equity and access issues. The City University of New York initially suspended classes for one week to allow faculty to retool courses for distance learning. Another break announced last week was prompted by the need to get laptops and tablets to students who need them, and to forestall the possibility that students without technology access might drop out.

At Los Angeles community colleges, the nation’s largest community college district serving 230,000 mostly poor students, classes also have been postponed as schools scramble to purchase and distribute technology to students and faculty. Fewer than half the system’s instructors have had any training in distance learning.

Before the crisis, web-based courses and technology platforms such as Blackboard were in use on almost every U.S. college campus. College rankings are based in part on the quality of technology infrastructure and connectivity.

Less is known about the scope of technology used in K-12 schools. About 310,000 students are enrolled in virtual schools, and another 420,000 students in brick-and-mortar schools take at least one online course from state-sponsored digital programs. But there’s little research on the vast number of students who use technology in classrooms with a live teacher according to the Aurora Institute, which studies educational innovation.

A 2010 study, one of the last to focus on the impact of online education on U.S. high schools, found that while online courses were then widely used to make up for lost academic credits, the quality of these courses was iffy. Students’ lack of self-discipline and command of math and reading skills may be another obstacle. Online courses are more successful when they allow schools to provide courses they otherwise could not.

Yet an international comparison of 15-year-olds in 31 countries found that “where it is more common for students to use the internet at school for schoolwork, students’ performance in reading declined.”

Earlier online experiments, such as New York City’s Innovation Zone, launched in 2010, demonstrate both the challenges of designing engaging online education programs and why a chief benefit of technology is to expand connections among students, teachers and the outside world.

The most successful iZone schools were educator-led efforts reliant on philanthropic funding that used technology as part of a broader strategy to rethink curriculum — in particular to develop interdisciplinary projects in longer time-blocks than the traditional 50-minute class, and to use technology to reach beyond school walls. For example, at Manhattan’s NYC iSchool, one nine-week module had students work on an exhibition for the National September 11 Memorial and Museum at Ground Zero. They began by studying the history of conflict between Islamic and Western civilizations. Students then used videoconferences to interview young people around the world about their views of the terrorist attacks.

Ultimately, the iZone expanded too rapidly and eventually unraveled — though the best schools continue to pursue innovative education strategies.

Fostering person-to-person connections using apps like Zoom and Google Classroom are especially important now. Teachers accustomed to dominating classroom discussions will find that difficult. Instead, with standardized tests suspended and test-prep pressures eased, teachers can assign independent or small-group projects using phone and video for feedback.

Tools like Google docs also “have the capacity to significantly improve teacher feedback and interaction with students,” says Nick Siewert, a consultant with Learning Matters. This is a time for educators and districts to document their education-technology experiences. After the crisis, the U.S. should finance systematic research on what worked and what didn’t, and expand its internet-funding programs.