PORTLAND — Dozens of school districts around the country have been giving iPads to students, to mixed reviews.

Schools in Omaha, Neb.; Columbiana, Ohio; Huntington, W. Va.; Paducah, Ky.; Charleston, S.C.; and Scottsdale, Ariz., are among the places where kindergarten pupils are using them.

Not everyone is sold. Larry Cuban, professor emeritus of education at Stanford University and the author of “Oversold and Underused: Computers in Schools,” said there’s no proof that computers bring learning benefits to pupils in kindergarten.

“There’s no evidence in research literature that giving iPads to 5-year-olds will improve their reading scores,” he said.

Peter Pizzolongo of the National Association for the Education of Young Children, based in Washington, said iPads can be an effective supplement to three-dimensional objects, whether they be books or building blocks.

“We can’t say whether what the school district in Maine or anywhere else is doing is good or not good, but what we can say is when the iPad or any other technological tool is used appropriately, then it’s a good thing for children’s learning,” he said.

The best use of iPads is probably in elementary and special education classes because the devices are so easy to use, said Nick Sauers of Iowa State University’s Center for the Advanced Study of Technology Leadership in Education. There are hundreds of education apps to choose from with a touch to the screen.

Sauers expects a boom soon, with most current iPad initiatives being billed as pilot or experimental programs.

“I think next year is when we’ll see our first big bubble,” Sauers said. “There will be districts next year that implement it school-wide, whether it be at the high school level or elementary level.”