News, or media, literacy — how to critically understand, analyze and evaluate online content, images and stories — is not new. But it has taken on urgency in the last few years as accusations of fake news and the reality of disinformation permeate the internet and people — especially young ones — spend hours and hours a day looking at screens.

[How News-Literate Are You? Take the Quiz to Find Out.]

“Media literacy is the literacy of the 21st century,” said a recent report by the nonprofit group Media Literacy Now.

Research has shown that an inability to judge content leads to two equally unfortunate outcomes: People believe everything that suits their preconceived notions, or they cynically disbelieve everything. Either way leads to a polarized and disengaged citizenry.

Other recent research suggests that while so-called digital natives — preteens and teenagers — are technically savvy, most of them fail when it comes to assessing the veracity of news articles and images.

“If they were on a highway, it would be equivalent to not knowing you should stop at a stop sign. That’s really the state of ignorance we’re dealing with,” said Sam Wineburg, a professor of education at Stanford University and executive director of the Stanford History Education Group, a research and development consortium.

The issue is being attacked by dozens of organizations offering information and curriculums on the subject. According to Media Literacy Now, 14 states require some sort of media literacy education in elementary and secondary schools.

One such program, the News Literacy Project — which began more than 10 years ago and works with news organizations (including The New York Times) to educate students in grades six through 12 — has grown rapidly since the 2016 election and is now offering online courses across the country.

“The election was a sea change,” said Alan Miller, the program’s founder and C.E.O., who won the 2003 Pulitzer Prize for national reporting at The Los Angeles Times.

In addition, several universities are working with middle and high schools and providing news literacy curriculums to them at no charge. College is too late to begin the lessons, said Howard Schneider, founding dean of the School of Journalism at the State University of New York at Stony Brook. He worked as a reporter and editor at Newsday for 35 years.

“Increasingly, students are arriving at college with bad digital citizenship habits,” he said. “They are outsourcing their judgment to their peers and to technology.”

Young people are not alone in their online illiteracy. A study last year found that those 65 and older shared more fake news during the 2016 election than younger adults.

The Stanford History Education Group has conducted some of the leading research into young people’s digital savvy, finding that a high proportion of students in middle school through college do not have the tools to evaluate the truth of online content.

Spurred by the group’s 2016 research findings, Google’s charitable arm funded a coalition called MediaWise that included the Stanford History Education Group, the Poynter Institute for Media Studies and the Local Media Association.

As part of the coalition, Stanford developed the curriculum, Civic Online Reasoning for middle and high school students. The goal is broader than just the media, but focused “on how we become informed about the issues of public policy that affect our lives,” Professor Wineburg said.

The aim of the Civic Online Reasoning curriculum is to get students to ask three basic questions when reading or watching online content: Who is behind that information? What is the evidence? What do other sources say?

Researchers focused on two major skills. The first is lateral reading. It encourages readers who come to an unfamiliar website to refrain from exploring the site more deeply until they have opened other tabs and found other websites to help them determine the authenticity or reliability of the newly discovered site.

The other skill is click restraint. Ideally, users would resist the impulse to click on the first results that appear in say, a Google search, until they have scanned the full list for credibility and then click selectively.

Professor Wineburg said that he learned these skills from professional fact checkers and that “focusing on a very small set of high-leverage skills can make a dent in students’ abilities to make wise judgments.”

Robert White, a government and politics teacher at a high school in Lincoln, Neb., was part of a pilot program for the curriculum and has taught it for the last three semesters. He says it works.

“Most students believed what they saw on a news site, any news site,” Mr. White said. “By the end of the semester, I could see a lot of change — they questioned any media source and did fact-checking. I now have students fact-checking me.”

In the last 18 months, another university-level news literacy program, Stony Brook’s Center for News Literacy, has reached out to secondary school staff members and teachers, offering them its summer academy, which runs about four days.

The idea of a journalism school now should be “not only teach the journalists of the future, but to prepare the audience of the future,” Professor Schneider said.

Carmen Amador, the principal of I.S. 303, learned about the Stony Brook news literacy program at a conference and attended the academy when it was still aimed at higher education. Using what she learned there, her school adopted a news literacy curriculum seven years ago.

“Before they started talking about fake news, we were talking about it,” Ms. Amador said. “But after 2016, the teachers became more excited and passionate about it.” The goal, she said, is not only to better understand the news but also to take action through community service and other initiatives.

Students are taught to know the “neighborhood” they’re reading in: is it journalism, entertainment, promotion, raw information or advertising? And an acronym, IMVAIN, is used widely as a cue: Are sources independent, are there multiple sources, do they verify evidence, and are they authoritative, informed and named sources?

“This generation is very disillusioned by news — everything is fake news,” said Maria Carnesi, district chairman of social studies at the Plainview-Old Bethpage school district, which is Stony Brook’s first demonstration district on Long Island. “News literacy is really empowering for young people."

In 2016, the News Literacy Project started offering a virtual classroom, Checkology, aimed at grades six through 12. The program offers 13 online interactive lessons that teachers can use. It began a partnership with New York City schools last fall.

So far, more than 20,000 educators and 140,000 students have registered to use Checkology nationwide and internationally, Mr. Miller said. The cost is $3.50 to $5 a student, depending on how many students are registered.

Brian Winkel, a high school journalism and English teacher in Cedar Falls, Iowa, uses Checkology in an elective course called 21st Century Literacy. He said he wished every student would be required to learn news literacy.

No long-term studies have been done on the effectiveness of teaching news literacy. But assessments of students before and after they complete courses and comparisons with students who do not take the classes show that students who learn news literacy are often better able to recognize false content and judge if a source of information is credible, and they are often more engaged in current events and news.

Students at I.S. 303, who are fast becoming more proficient than some adults in evaluating online content, now see a need to teach their peers and parents.

“My mom doesn’t watch the news all that much, but sometimes she’ll read something, and she’ll automatically believe it and tell me about it,” said Nafisa Patwary, a seventh grader. “And I’ll help her fact check.”