When Education Secretary Betsy DeVos arrived in Omaha last month for her back-to-school tour, she bypassed the city's 82 public schools and decided instead to go to Nelson Mandela Elementary, a tuition-free private school.

There, unlike students in nearby public schools, "scholars" at Nelson Mandela attend class year-round, take violin lessons — learning works composed specially by a local conservatory — and get swim and golf lessons in the summertime. The school serves just 180 children, who get in by lottery, and has a long waiting list.

For Bryan High, a public school in Omaha that had received a call from the Education Department inquiring about a possible visit, it hurt to be passed over by the secretary.

"I was very excited for the opportunity to show her that Bryan is very diverse and a great place to be, and for public schools in general, to show her that they're not as bad everyone else makes them seem," said Karen O'Connor, 16, the senior class president. "I know she's a very rich woman who has never gone to public school. It was a chance for us to finally prove ourselves."

Since becoming the nation's schools chief earlier this year, DeVos has visited 37 K-12 schools — and about one-fourth have been private or religious, even though such schools educate just one-tenth of the nation's schoolchildren.

Neither DeVos nor the Education Department have much say in what happens in the nation's private and religious schools, which have wide latitude in selecting students and are not bound by federal education laws that require public schools to show how much their students are learning.

Her focus on private schools became especially stark during a whirlwind back-to-school trip she called the Rethink School tour: Five of the 13 schools and universities she visited are private. At the start of the tour, she assailed most of the schools that educate U.S. children as pushing an antiquated model of education.

"Most students are starting a new school year that is all too familiar. Desks lined up in rows," DeVos told students at Woods Learning Center in Casper, Wyo., a public school that is run by teachers but that has no principal. "Their teacher standing in front of the room, framed by a blackboard. They dive into a curriculum written for the 'average' student. They follow the same schedule, the same routine — just waiting to be saved by the bell. It's a mundane malaise that dampens dreams, dims horizons and denies futures."

DeVos stands apart from her predecessors for many reasons: She has never worked in a public school and comes from immense wealth, crisscrossing the country in her personal aircraft. She also visits far more private schools.

Arne Duncan, who held the job from 2009 to 2015, visited 34 K-12 public schools and one private early learning center during his first 8 1 / 2 months in office.

Over the past eight months, DeVos has traveled the country to learn about the nation's schools, reading books to youngsters at Ashland Elementary in Virginia, taking in a high school football game in Indiana and comforting educators following a shooting at an elementary school in San Bernardino, Calif.

She's also visited Catholic, Episcopal and other kinds of Christian schools, some of which benefit from tax-credit scholarships and vouchers — controversial policies that steer public money into private schools. Her efforts to direct public dollars to private schools trouble some civil rights advocates because she has not been clear on whether she believes private schools that receive taxpayer funds should comply with civil rights laws.

Her visits are often marked by ferocious protests from local parents, teachers unions and college students, riled by her recent decision to roll back guidelines on how schools should investigate sexual assault.

DeVos's spokesman, Nathan Bailey, defended the time the secretary spends in private schools, even when her department has little purview over them.

"The department doesn't 'have a lot of say' in most schools. Education policy, education funding is handled primarily at the state and local level," Bailey said. "It's not as if she's going to conduct oversight audits. She's going to learn about the kind of programs that are meeting the unique needs of individual children."

Even when DeVos has visited public schools, she has tended to bypass traditional neighborhood schools, instead making stops at charter schools and other schools of choice, such as magnet schools. Bailey said DeVos hopes to raise the profile of all schools that are pursuing innovative strategies that inspire parents, educators and policymakers.

For advocates of traditional public schools, DeVos's visits are another sign she cares more about ensuring that parents can choose where their child goes to school than about the quality of the schools that educate the vast majority of young people. DeVos proposed drastic cuts in money for after-school programs, career and technical education, and teacher preparation in favor of dedicating $400 million to expand charter schools and private school vouchers and more than $1 billion to push states to adopt policies friendly to school choice.

Bob Farrace, spokesman for the National Association of Secondary School Principals, said he was disappointed by where DeVos chose to stop during her back-to-school tour.

"It was more like dismantling schools then rethinking schools," Farrace said.

Those who represent private schools see the visits as necessary — and point out that about one-fourth of schools in the United States are private, even though they educate only about 10 percent of students.

"It's important for her to see what's going on in all schools," said Sister Dale McDonald, the director of public policy for the National Catholic Educational Association. "She is the secretary of education, not the secretary of public schools."

Her predecessors said school visits provided them with essential insights into the day-to-day functioning of schools that they took back to Washington and that led to concrete changes in policy. Duncan, managing partner of the Emerson Collective in Chicago, visited hundreds of schools while education secretary and said it was one of the most important parts of his job.

"You don't learn sitting behind your desk in Washington," Duncan said. "You learn by talking to real principals, real teachers, real kids."

Duncan said his eye-opening visits to schools running innovative vocational training programs — such as Worcester Tech in Massachusetts, which operates a hair salon and a credit union — "absolutely changed how we looked at vocational learning." His visit to a high school in Carrollton, Ga., where students ran a wire and cable factory on the first floor in partnership with a local manufacturer, led him to encourage other schools to adopt that model.

DeVos views her role as getting out of the way so that innovative teaching practices can occur — not encouraging them through federal policy. She has said she hopes her visits will highlight education models that parents and educators will bring to their own communities — regardless of what happens in Washington.

Bailey said the secretary's focus on private schools should not be construed as disdain for public schools: "She's always been supportive of high-performing, innovative, student-centered public schools. She's always said public schools will be a critical part of the future of education."

Some schools have welcomed DeVos — but with reservations. Susan Toohey, principal of Nelson Mandela Elementary in Omaha, has been critical of DeVos and was adamant the visit not be used to sell school choice or private school vouchers. The school's philanthropic backers are opposed to charter schools in Nebraska — which has none — and to private school vouchers. So Toohey sent a subtle message by having her students wear stickers on their uniforms that signaled support for public education, printed by the philanthropist who underwrites the school.

Toohey said she was pleased that DeVos visited Mandela, which the principal and the founders see as a testing ground for new types of instruction. But the visit did not change her view of DeVos, whom she regards as unfit for the job because of her lack of experience in public schools.

"There's trust when somebody believes that you've walked the walk," Toohey said.

Andrew Ba Tran contributed to this report.