Snow days, sick days and quarantine days are good times for students to learn by livestreaming their classes. That’s what Needham High student Rebecca Sugarman did when she was sick with COVID-19 in December, firing up her laptop to watch honors physics and math classes from her bedroom.

“For her it was kind of not a big deal,” said her mom, Lesley Sugarman. Rebecca knew the drill after spending much of last year learning remotely.

“She said that it was helpful to be able to see what was going on in class and to be able to kind of be more in the know,” Sugarman said, “as opposed to just having the teacher say we'll get you caught up when you get back.”

As simple as it sounds, livestreaming is not a universal option for students in Massachusetts or across the nation. In New York City, public schools offer remote learning on snow days and other emergencies when buildings are closed. In Los Angeles, sick students can livestream classes from home. The same is true of students attending public schools in the Boston suburbs of Needham and Weston, as well as private schools like Beaver Country Day in Newton.

That's not the case in Boston, Lowell, Lawrence and other cities and towns, raising concerns over yet another way the pandemic has disadvantaged some students more than others.

“It's really a question of which kids get access to that, and so there's a real equity question here,” said Robin Lake, director of the Center for Reinventing Public Education, a research center based at the University of Washington Bothell.

“Students and families like more flexibility in our school systems. They'd like the opportunity to stay connected to the classroom if they have to be home for some reason,” Lake said. She added that livestreaming is not ideal, "but if it's a question of no instruction or some instruction, I go for some instruction.”

Massachusetts education officials required all students to return to in-person classes this year, putting an end to remote learning. The exception to that rule allows schools — if they have the resources — to livestream classes to students who are sick or in quarantine.

Laurie DeVries' children have had opposite experiences this school year. Her daughter attends Pollard Middle School, a public school in Needham, which does not offer livestreaming. Her son attends Thayer Academy, a private school in Braintree, which tracks its teachers with 360-degree “Owl Pro” meeting cameras that automatically zoom in on whoever is speaking in a classroom.

“My son's experience was better for sure,” DeVries told GBH News. “I mean, he might not say that, but when he was done with school, we knew he was done with school.”

Researchers are still studying the benefits and drawbacks of remote learning, livestreaming and other new methods such as concurrent learning, which involves simultaneously teaching both remote and in-person students. Besides the issue of equity, Lake's research center found that students who attended school remotely for longer periods of time during the pandemic fell further behind those who did not. But livestreaming is generally defined as a window into a classroom, and it does not rely on a teacher interacting with students over video at home.

Some affluent suburban districts, like Newton, don’t offer any livestream options. Superintendent David Fleishman said he saw little use for the technology considering how few students would likely use it.

Beth Kontos, president of the American Federation of Teachers in Massachusetts, called livestreaming outright ineffective. She said it has the potential to ruin the in-person student experience. If a teacher specializing in project-based learning divides students into groups to conduct research or have discussions, which happens frequently, an entire in-person class may need to login to participate with one student who is livestreaming from home.

“It's ineffective,” Kontos said, noting how much students and teachers move around from group to group to discuss concepts.

“I know some people have it in their head that someone stands at the front of the classroom and talks for an hour," she said. "That just isn't the way education works anymore.”

Kontos added that many teachers aren't keen on having cameras follow them in classrooms eight hours a day. She said they don't know who could be watching besides their students.

Massachusetts Education Commissioner Jeffrey Riley blamed the teachers unions for refusing to let livestreaming take off.

“Right now, some districts have a contract with the teachers union that allows kids to livestream classes, and other teachers unions refuse to do that,” he said last month at a meeting of the state Board of Elementary and Secondary Education.

The Boston Teachers Union said in a statement that it "is absolutely in favor of remote learning options for students who are quarantined."

"We do not want to take away from the in-person experience by splitting teachers attention between the two groups of students," said Jessica Tang, president of the union. "Students at home deserve high-quality remote instruction, which they are not able to get if the teacher's attention is divided."

She added that the union has advocated for more positions to support remote teaching and learning and continues to advocate for remote learning options.

Roger Nugent, president of the Worcester Education Association, said he is against requiring teachers to juggle online and in-person students at the same time through hybrid, or concurrent, learning. But livestreaming could be a viable option, he said, if it isn’t disruptive.

“As long as it doesn't take away from meaningful instruction for kids. I think we'd be for that,” he said.

Wellesley teen Eleni Carris Livingston, the student representative on the state board of education, said she's been in communication with students who want livestreaming to be an option. She said as coronavirus testing in the schools improved, many asymptomatic students were forced to quarantine even though they felt fine. That is, except for anxiety about what they're missing.

“They're taking courses that are difficult for them,” Livingston told the board. “They know that if they aren't in school for five days, they're going to fall behind. It's an area of considerable stress.”