The most effective online classes are led by professors who show empathy for their students, according to John Mitchell, who chairs the computer science department at Stanford University.

“It's possible to pay attention to how people are doing and ask them how they're doing and find out," Mitchell said. "But it takes work. And so we're really trying to — in a much more difficult context — replace something that we've lost that's very valuable to us."

The pandemic forced many colleges to move their classes online in March. Professors who had never taught virtually before had to adapt quickly. So what’s working? What’s not?

Surveys show most students see online learning as a poor replacement for the classroom because they feel so isolated.

“It has been very lonely,” Sam Kunz, a graduate student at Harvard's Kennedy School of Government, told GBH News.

“At the beginning of the semester, it was most certainly the most stressful time of my life,” said Kunz, who was an undergraduate at a small liberal arts college. “When that spotlight is on you in a Zoom room, you’re blown up on everyone’s screen. So you get one shot, and you don’t want to waste it.”

To hear the full story, click on the audio player above.

Diane Adame contributed to this report.