A little more than half of U.S. elementary and high school students will attend school only virtually this fall, according to a new study, as education officials struggle with an unprecedented and wrenching decision amid the coronavirus pandemic.

The study by Burbio, which aggregates school and community calendars nationwide, found that 52% of students will go to school virtually only and just 25% will attend every day. The remaining 19% will have some form of hybrid schooling, combining online and in-person learning. Four percent of districts remain undecided.