In Anchorage, affluent families set off on ski trips and other lengthy vacations, with the assumption that their children can keep up with schoolwork online.

In a working-class pocket of Michigan, school administrators have tried almost everything, including pajama day, to boost student attendance.

And across the country, students with heightened anxiety are opting to stay home rather than face the classroom.

In the four years since the pandemic closed schools, U.S. education has struggled to recover on a number of fronts, from learning loss, to enrollment, to student behavior.

But perhaps no issue has been as stubborn and pervasive as a sharp increase in student absenteeism, a problem that cuts across demographics and has continued long after schools reopened.

Nationally, an estimated 26 percent of public school students were considered chronically absent last school year, up from 15 percent before the pandemic, according to the most recent data, from 40 states and Washington, D.C., compiled by the conservative-leaning American Enterprise Institute. Chronic absence is typically defined as missing at least 10 percent of the school year, or about 18 days, for any reason.

The increases have occurred in districts big and small, and across income and race. For districts in wealthier areas, chronic absenteeism rates have about doubled, to 19 percent in the 2022-23 school year from 10 percent before the pandemic, a New York Times analysis of the data found.

Poor communities, which started with elevated rates of student absenteeism, are facing an even bigger crisis: Around 32 percent of students in the poorest districts were chronically absent in the 2022-23 school year, up from 19 percent before the pandemic.

Even districts that reopened quickly during the pandemic, in fall 2020, have seen vast increases.

“The problem got worse for everybody in the same proportional way,” said Nat Malkus, a senior fellow at the American Enterprise Institute, who collected and studied the data.

The trends suggest that something fundamental has shifted in American childhood and the culture of school, in ways that may be long lasting. What was once a deeply ingrained habit — wake up, catch the bus, report to class — is now something far more tenuous.

“Our relationship with school became optional,” said Katie Rosanbalm, a psychologist and associate research professor with the Center for Child and Family Policy at Duke University.

The habit of daily attendance — and many families’ trust — was severed when schools shuttered in spring 2020. Even after schools reopened, things hardly snapped back to normal. Districts offered remote options, required Covid-19 quarantines and relaxed policies around attendance and grading.

Today, student absenteeism is a leading factor hindering the nation’s recovery from pandemic learning losses, educational experts say. Students can’t learn if they aren’t in school. And a rotating cast of absent classmates can negatively affect the achievement of even students who do show up, because teachers must slow down and adjust their approach to keep everyone on track.

“If we don’t address the absenteeism, then all is naught,” said Adam Clark, the superintendent of Mt. Diablo Unified, a socioeconomically and racially diverse district of 29,000 students in Northern California, where he said absenteeism has “exploded” to about 25 percent of students. That’s up from 12 percent before the pandemic.

Why Students Are Missing School

Schools everywhere are scrambling to improve attendance, but the new calculus among families is complex and multifaceted.

At South Anchorage High School in Anchorage, where students are largely white and middle-to-upper income, some families now go on ski trips during the school year, or take advantage of off-peak travel deals to vacation for two weeks in Hawaii, said Sara Miller, a counselor at the school.

For a smaller number of students at the school who qualify for free or reduced-price lunch, the reasons are different, and more intractable. They often have to stay home to care for younger siblings, Ms. Miller said. On days they miss the bus, their parents are busy working or do not have a car to take them to school.

And because teachers are still expected to post class work online, often nothing more than a skeleton version of an assignment, families incorrectly think students are keeping up, Ms. Miller said.

Across the country, students are staying home when sick, not only with Covid-19, but also with more routine colds and viruses.

And more students are struggling with their mental health, one reason for increased absenteeism in Mason, Ohio, an affluent suburb of Cincinnati, said Tracey Carson, a district spokeswoman. Because many parents can work remotely, their children can also stay home.

For Ashley Cooper, 31, of San Marcos, Texas, the pandemic fractured her trust in an education system that she said left her daughter to learn online, with little support, and then expected her to perform on grade level upon her return. Her daughter, who fell behind in math, has struggled with anxiety ever since, she said.

“There have been days where she’s been absolutely in tears — ‘Can’t do it. Mom, I don’t want to go,’” said Ms. Cooper, who has worked with the nonprofit Communities in Schools to improve her children’s school attendance. But she added, “as a mom, I feel like it’s OK to have a mental health day, to say, ‘I hear you and I listen. You are important.’”

Experts say missing school is both a symptom of pandemic-related challenges, and also a cause. Students who are behind academically may not want to attend, but being absent sets them further back. Anxious students may avoid school, but hiding out can fuel their anxiety.

And schools have also seen a rise in discipline problems since the pandemic, an issue intertwined with absenteeism.

Dr. Rosanbalm, the Duke psychologist, said both absenteeism and behavioral outbursts are examples of the human stress response, now playing out en masse in schools: fight (verbal or physical aggression) or flight (absenteeism).

Quintin Shepherd, the superintendent in Victoria, Texas, first put his focus on student behavior, which he described as a “fire in the kitchen” after schools reopened in August 2020.

The district, which serves a mostly low-income and Hispanic student body of around 13,000, found success with a one-on-one coaching program that teaches coping strategies to the most disruptive students. In some cases, students went from having 20 classroom outbursts per year to fewer than five, Dr. Shepherd said.

But chronic absenteeism is yet to be conquered. About 30 percent of students are chronically absent this year, roughly double the rate before the pandemic.

Dr. Shepherd, who originally hoped student absenteeism would improve naturally with time, has begun to think that it is, in fact, at the root of many issues.

“If kids are not here, they are not forming relationships,” he said. “If they are not forming relationships, we should expect there will be behavior and discipline issues. If they are not here, they will not be academically learning and they will struggle. If they struggle with their coursework, you can expect violent behaviors.”

Teacher absences have also increased since the pandemic, and student absences mean less certainty about which friends and classmates will be there. That can lead to more absenteeism, said Michael A. Gottfried, a professor at the University of Pennsylvania Graduate School of Education. His research has found that when 10 percent of a student’s classmates are absent on a given day, that student is more likely to be absent the following day.

Is This the New Normal?

In many ways, the challenge facing schools is one felt more broadly in American society: Have the cultural shifts from the pandemic become permanent?

In the work force, U.S. employees are still working from home at a rate that has remained largely unchanged since late 2022. Companies have managed to “put the genie back in the bottle” to some extent by requiring a return to office a few days a week, said Nicholas Bloom, an economist at Stanford University who studies remote work. But hybrid office culture, he said, appears here to stay.

Some wonder whether it is time for schools to be more pragmatic.

Lakisha Young, the chief executive of the Oakland REACH, a parent advocacy group that works with low-income families in California, suggested a rigorous online option that students could use in emergencies, such as when a student misses the bus or has to care for a family member. “The goal should be, how do I ensure this kid is educated?” she said.

In the corporate world, companies have found some success appealing to a sense of social responsibility, where colleagues rely on each other to show up on the agreed-upon days.

A similar dynamic may be at play in schools, where experts say strong relationships are critical for attendance.

There is a sense of: “If I don’t show up, would people even miss the fact that I’m not there?” said Charlene M. Russell-Tucker, the commissioner of education in Connecticut.

In her state, a home visit program has yielded positive results, in part by working with families to address the specific reasons a student is missing school, but also by establishing a relationship with a caring adult. Other efforts — such as sending text messages or postcards to parents informing them of the number of accumulated absences — can also be effective.

In Ypsilanti, Mich., outside of Ann Arbor, a home visit helped Regina Murff, 44, feel less alone when she was struggling to get her children to school each morning.

After working at a nursing home during the pandemic, and later losing her sister to Covid-19, she said, there were days she found it difficult to get out of bed. Ms. Murff was also more willing to keep her children home when they were sick, for fear of accidentally spreading the virus.

But after a visit from her school district, and starting therapy herself, she has settled into a new routine. She helps her sons, 6 and 12, set out their outfits at night and she wakes up at 6 a.m. to ensure they get on the bus. If they are sick, she said, she knows to call the absence into school. “I’ve done a huge turnaround in my life,” she said.

But bringing about meaningful change for large numbers of students remains slow, difficult work.

The Ypsilanti school district has tried a bit of everything, said the superintendent, Alena Zachery-Ross. In addition to door knocks, officials are looking for ways to make school more appealing for the district’s 3,800 students, including more than 80 percent who qualify for free or reduced-price lunch. They held themed dress-up days — ’70s day, pajama day — and gave away warm clothes after noticing a dip in attendance during winter months.

“We wondered, is it because you don’t have a coat, you don’t have boots?” said Dr. Zachery-Ross.

Still, absenteeism overall remains higher than it was before the pandemic. “We haven’t seen an answer,” she said.

Selective colleges and universities can no longer use race-based preferences in admissions to create a more diverse student body. But what if they gave a break instead to lower-income students? Or those from high-poverty schools? Or those who do relatively well academically despite challenges all around them?

To explore those questions — and how much racial diversity is possible without “race-conscious” admissions — the Upshot worked with Sean Reardon, a professor at Stanford, and Demetra Kalogrides, a senior researcher there, to model four alternatives to affirmative action.

The scenarios shown here are based on the real-life academic and demographic characteristics of the high school class of 2013 in America, the most recent tracked over time by a large nationally representative survey. We used this data set, further adjusted to reflect the rising diversity of students in the decade since, to simulate a representative class of 10,000 high school seniors. We then modeled their admissions prospects to the group of colleges (Barron’s Tier 1 schools) that rank as the most selective in the country — and that have also been most affected by the Supreme Court’s ruling.

Throughout, we use SAT scores as a simplified measure of academic merit (after test scores fell out of favor with many colleges during the pandemic, several of the most selective schools have recently returned to requiring them).

Our models simplify the complex and often opaque ways that selective colleges craft admissions (we also reserve no seats for athletes on scholarship or legacy students). But even a stripped-down exercise shows why some approaches to admissions would probably yield more diversity than others, by both race and class.

Let’s start with the simplest model and build from there:

Scenario 1 of 4: A preference for poorer students

In this scenario, we give a moderate boost to applicants on a sliding scale according to their parents’ income: from an extra 150 points for students from the poorest families, to 0 points for students from the richest ones. This creates the slope of the cutoff line you see above.

Because each of our scenarios admits a fixed class of 500 students, the results are zero-sum: As some students are newly admitted, others who might have been admitted under different policies no longer are. The magnitude of that effect — and whom it touches — differs depending on the criteria.

In this case, as more low-income students are admitted, some high-income students with SAT scores just above 1300 no longer get in. That trade-off creates significantly more economic diversity, as this table shows:

The share of admitted students from the top income quartile falls by about 12 percentage points.

But the shifts toward racial diversity are modest. The Black student share rises by just one percentage point. Why? Black families are over-represented among poorer households in America, but in terms of total numbers, there are still many more poorer white households.

For this reason, income is a relatively weak proxy for race in admissions. A preference for lower incomes produces just that: students with lower incomes, not necessarily a much larger share of Black or Hispanic students.

In this scenario, a total of 13 percent of students in the admitted class are Black or Hispanic. For context, Americans of high-school-graduation age today are about 38 percent Black or Hispanic.

It’s also worth emphasizing that we are modeling who gets admitted, not who enrolls. And Black and Hispanic students are less likely to take that additional step — enrolling in a selective college that might be expensive or far from home, even if they get in.

Scenario 2 of 4: Adding school poverty

In addition to a preference for low-income students, what if we added a preference for those who attend higher poverty schools?

This scenario takes the 150-point income preference in Scenario 1 and adds a second 150-point preference for students in higher-poverty schools, as measured by the share of students in that school receiving free or reduced-price lunch. A low-income student in a high-poverty school could get as much as a 300-point boost.

This produces even more economic diversity than the preference for parental income alone. And it further nudges up the share of admitted Black and Hispanic students.

We know that students with equally low family incomes differ from each other in many ways. For example, low-income Black and Hispanic students are more likely than low-income white and Asian students to live in high-poverty neighborhoods and attend high-poverty schools.

And so if one goal of an admissions policy is to account for the compound disadvantages minority students often face, it may help to pull in more information: not just about their parents’ incomes, but also about their households, schools and neighborhoods.

Colleges could further hone a preference like this by pulling in more factors, including neighborhood poverty rates, parental education levels and parental wealth.

Do something like that, and “now you have a group of students who have overcome a lot more in life than the ones who have just been handed everything,” said Richard Kahlenberg, a researcher at the Progressive Policy Institute who has argued for this kind of robust class preference. He also served as an expert witness critiquing race-based admissions in the litigation that led to the Supreme Court decision.

Scenario 3 of 4: Finding the outliers

It’s possible to take the underlying idea in Scenario 2 and dial it up further, by identifying students who outperform their peers with similar disadvantages (or similar advantages).

Here, we’re not just giving a boost to students who come from disadvantage. We’re rewarding students who perform better academically than other students with similar backgrounds.

This strategy identifies, for example, a student who has an 1100 SAT score — but whose score is 250 points above the typical student who also goes to a high-poverty high school and who has low-income parents who didn’t attend college. This strategy also discounts some of the wealthiest students whose 1400 scores look less impressive when compared with their equally well-off peers.

Students who outperform their peers are academic outliers, and that may indicate something special about them: “We’re admitting students on the basis of striving: students whose academic achievement exceeded expectations based on the access to opportunity that they had,” said Zack Mabel, a Georgetown researcher who has modeled admissions scenarios similar in concept to this one.

Of the scenarios tested so far, this one does the most to produce both economic and racial diversity, compared with admitting students on test scores alone. It also produces significant shifts among high-income white students; their share of the admitted class is 27 percentage points lower than it would be in a test-only environment. The resulting average SAT score of the admitted class is also the lowest of the scenarios so far, at 1340.

To gauge how we’d expect students to perform in this scenario, we take into account their parental income, school poverty level and a socioeconomic index that includes parents’ education levels and occupations. We use that data to predict each student’s SAT score. Then we admit the students who outperformed those predictions by the largest margins (until we’ve admitted 500 of them).

A college that cares more about keeping a higher average SAT score could use a limited version of a preference like this one. A school that believes students who beat the odds in high school are likely to succeed in college could embrace a fuller version.

Remember that in this scenario and each of the preceding ones, we’ve considered only students who apply to highly selective colleges (the national study we use as a reference shows which students actually did). We have effectively ignored all of the students shown below who don’t apply, including some with pretty good grades and test scores:

Next, let’s think about that group, too.

Scenario 4 of 4: Casting a wider net

What happens when colleges try to expand the applicant pool?

To create this scenario, we expanded the pool of applicants to selective colleges by modeling a recruiting strategy targeted at predominantly minority high schools.

First, we pull into the applicant pool all students of any race with SAT scores above 1000 at high schools where at least three-quarters of students are nonwhite. Then we rerun the preference for beating the odds from Scenario 3 with this larger applicant pool.

This strategy most notably captures more Hispanic students, and it produces by far the biggest shift toward lower-income students. It broadly redistributes seats held in an SAT-only scenario by high-income white students and, to a lesser degree, high-income Asian ones.

Although colleges can no longer employ racial preferences in admissions, several legal scholars said they believe schools can still consider race in recruiting strategies. The Supreme Court, in turning away another recent legal challenge, has also signaled — at least for now — that it’s permissible for colleges to pursue diversity as an end goal so long as racial preferences aren’t the means to achieve it.

Of the scenarios we’ve shown, an expanded recruiting strategy requires the most work from colleges. But it’s also “the big overlooked gold mine here,” said Richard Sander, a law professor at U.C.L.A. who has worked on admissions strategies at the law school level.

Such a recruiting strategy would mean not just tweaking statistical preferences, but also building relationships with high school counselors, traveling to college fairs, and perhaps developing dual-enrollment courses that introduce high school students to college work.

This kind of outreach — “to me, it’s everything,” said Jill Orcutt, the global lead for consulting with the American Association of Collegiate Registrars and Admissions Officers. She was previously the associate vice chancellor for enrollment at U.C. Merced, the most diverse school in the University of California system.

Comparing our scenarios

In evaluating the impact of the scenarios shown here, we’ve compared each one with the SAT-only baseline in which colleges consider a form of academic merit and nothing else. But it’s also helpful to think about these scenarios in another way — in comparison to the world as it might look if affirmative action were still legal.

To make that comparison, we also created a model approximating the effects of affirmative action. We took the same 150-point boost we’ve used in earlier scenarios, and we applied it to Black and Hispanic students. Real-world affirmative action policies were more complicated than this. But studies have found that such policies gave Black and Hispanic students higher odds of admission equivalent to an SAT score boost of a few hundred points.

Across all our models, Scenario 4 — rewarding students who are academic outliers given their life circumstances, while targeting a wider pool of recruits — comes the closest to creating the Black and Hispanic student shares you might get by giving a boost directly to those students:

Notably, our simple affirmative action model produces far less economic diversity than all of these alternatives. That was also a frequent criticism of such policies: Yes, colleges used them to admit more Black and Hispanic students, but those were overwhelmingly middle- and upper-income students. In our affirmative action model, just 6 percent of admitted students come from the bottom quartile of the income distribution. That’s almost identical to the share of such students who were enrolled in the real world across these selective colleges, according to a 2017 report.

To be clear, our simplified affirmative action model also suggests selective colleges would admit a far higher share of Black and Hispanic students — nearly 34 percent — than were actually in the incoming class of 2022 (23 percent across this top tier of selective schools). That’s because our model captures the upper bound of what’s possible with such a strategy.

Some schools that were already heavily investing in expanded recruiting, like Johns Hopkins, were actually close to or even above this number. Other selective colleges that devoted more seats to legacy students and fewer resources to minority recruiting or financial aid had much lower shares. Our model, in its simplicity, effectively treats all of these varied schools as if they act in unison.

The scenarios illustrated here can’t predict what will happen next — this is a model after all, if one based on real demographics. But this exercise reveals some broad lessons that probably translate to the real world: Income by itself is a weak stand-in for race. Neighborhood and school-level data can help identify minority students. And the potential of any admissions strategy is limited without casting a wider recruiting net.

The questions affecting each admissions parameter are also murky. Does more economic diversity replace some of what colleges lose with less racial diversity? Should students be evaluated in the context of all their disadvantages? How much should colleges yield on lower measures of academic merit to gain the advantages of a diverse campus?

Individual colleges will answer these questions in different ways. And they will do so considering factors, including financial aid and legacy admissions, that are more complex than the ones we modeled. But they’ll also have access to a lot more data than we do about each prospective student in trying to fine-tune what comes next. We will soon see what they do with it.