WASHINGTON — Children have welcomed the Harry Potter books in recent years like free ice cream in the cafeteria, but the largest survey ever of youthful reading in the United States today will reveal that none of J.K. Rowling's phenomenally popular books has been able to dislodge the works of longtime favorites Dr. Seuss, E.B. White, Judy Blume, S.E. Hinton and Harper Lee as the most read.

Books by the five well-known U.S. authors, plus lesser-known Laura Numeroff, Katherine Paterson and Gary Paulsen, drew the most readers at every grade level in a study of 78.5 million books read by more than 3 million children who logged on to the Renaissance Learning Web site to take quizzes on books they read last year. Many works from Rowling's Potter series turned up in the top 20, but other authors also ranked high and are likely to get more attention as a result.

"I find it reassuring ... that students are still reading the classics I read as a child," said Roy Truby, a senior vice president for Wisconsin-based Renaissance Learning. But Truby said he would have preferred to see more meaty and varied fare, such as "historical novels and biographical works so integral to understanding our past and contemporary books that help us understand our world."

WHERE'S NONFICTION?

Michelle Bayuk, marketing director for the New York-based Children's Book Council, agreed. "What's missing from the list are all the wonderful nonfiction, informational, humorous and novelty books as well as graphic novels that kids read and enjoy both inside and outside the classroom."

Renaissance Learning's Accelerated Reader software for monitoring reading progress online was the source of the survey. Twenty-two years ago, Judi Paul invented on her kitchen table a quizzing system to motivate her children to read. With her husband, Terry Paul, she turned it into a big business. Truby, a former executive director of the National Assessment Governing Board, which oversees the leading federal reading test, said the company's learning programs are used in more than 63,000 U.S. schools.

Students read books, some assigned but many chosen on their own, and then take computer quizzes, either online or with company software, to see whether they understood what they read. Students compile points based on the average sentence length, average word length, word difficulty level and total words in each book, and they sometimes get prizes from their schools. Some critics have questioned giving many more points for a sprawling Tom Clancy thriller than a tightly written classic such as Stephen Crane's "The Red Badge of Courage," but many educators and parents have praised the system for motivating children to read.

In response to the survey data, some Washington-area English teachers said they were bothered by the relatively few books read by each student, particularly in the upper grades. Seventh-graders averaged 7.1 books in 2007, a rate that steadily declined to 4.5 books for 12th-graders. "I wish more schools did what we do and treated independent reading as vital to the curriculum, especially for boys, who seem to be sharing very few books," said Lelac Almagor, a seventh-grade teacher at the KIPP DC: AIM Academy, a public charter school in Washington.

Although some experts thought children needed more reality, the fifth-most-popular book among high school students, "A Child Called 'It' " by Dave Pelzer, was too real for Rachel Sadauskas, who teaches English at Yorktown High School in Arlington, Va. "The true story is based on a brutal case of child abuse," she said. "A friend who is a social worker recommended it to me, but I could not finish it because it was so emotionally difficult to read."

CAN'T KILL 'MOCKINGBIRD'

Teachers and book editors were pleased at the resilience of Lee's 48-year-old novel, "To Kill a Mockingbird," No. 1 for ninth- through 12th-graders, though Mary Lee Donovan, an executive editor at Candlewick Press in Somerville, Mass., said she thought it owed much of its success to the fact that "teachers make it part of the curriculum." Rafe Esquith, teacher and author of best-selling books about teaching, makes it required reading in his Los Angeles fifth-grade class. He said he thought older students preferred it to Harry Potter because it fits with their growing realization that "life is not a fairy tale" and because of the moral fiber of its hero, lawyer Atticus Finch.

Arlington Yorktown High 11th-grader Ashley Samay said the Lee book "taught me to see things from others' points of view." Yorktown 12th-grader Matthew Bloch said, "It speaks to small-town ideals and racism, which are very important topics."

The survey, at www.renlearn.com/whatkidsarereading, breaks down results by gender and section of the country. Overall, Dr. Seuss' madly rhyming "Green Eggs and Ham" was the most popular first-grade book. Second-graders preferred Numeroff's "If You Give a Mouse a Cookie," which Donovan praised for its humorous take on cause and effect. White's timeless tale of a girl, a pig and a spider, "Charlotte's Web," was the third-grade favorite. Blume, not surprisingly, won over fourth-graders with her "Tales of a Fourth Grade Nothing," the first of several books about Peter Warren Hatcher, who prefers to be called "Fudge."

Fifth-graders read most often Paterson's story of two children and a magical forest kingdom, "Bridge to Terabithia." Sixth-graders preferred "Hatchet," about a boy stranded in the wilderness, by Paulsen, whom Donovan called "Jack London for kids." The most-read book among seventh- and eighth-graders was "The Outsiders," a story of rival gangs in Tucson published in 1967 when its author, Hinton, was 18 years old.