A new national study reports that more than a third of college students who started in 2008 transferred to another school.

That challenges ideas about the typical college trajectory and is stoking debate about how schools should help transfer students.

Researchers at the nonprofit National Student Clearinghouse Research Center found that out of 3.6 million U.S. students in the study, 37 percent transferred at least once within six years. Of those students, almost half transferred more than once.

The study's authors say students don't see colleges as a permanent home for their education anymore. They added that the national measures used to grade colleges often omit transfer students but will likely need to be revised.

A 2014 report by the U.S. Department of Education found that students often lose credits when they transfer from one school to another.