Video games are increasingly popular learning tools in classrooms, but not all teachers are sold on the benefits.

Day two of NBC’s Education Nation summit highlighted the potential for video games to tailor material to a student’s individual level and allow teachers to track student progress. But while games can provide valuable information about how students learn, there is still little evidence that video games positively impact student achievement. And many teachers are skeptical about incorporating games in the classroom, even if it means students would be more invested in lessons.

During a Monday panel on gaming in the classroom, educators brought up some of their main concerns with the emerging technology. Todd Beard, a K-12 technology teacher in Flint, Mich., said his students have trouble transferring skills they learn playing educational games in class to paper-based tests. While his students may appear to master skills during a video game, they forget it when they’re taking an assessment later. Beard tells his students, “It’s the same thing, you just did that,’” he said. He believes his students aren’t as invested in tests because they aren’t as fun as the games. “I feel like they’re learning [skills], but I have to prove that on an assessment,” Beard added.

Children ages 8 to 18 spend an average of 7.5 hours a day using entertainment media, so some teachers say parents don’t want their kids spending more time playing video games at school. And funding can be an issue for some schools. “We pay for the [gaming] sites,” said Lyssa Sahadevan, a first-grade teacher in Marietta, Ga., speaking to The Hechinger Report after the panel. “So that’s a challenge.”

While Sahadevan says she has seen her first-graders transfer their skills from games to tests, she has struggled to find games that assess students as they play, so kids may spend time on a level that is too high or too low for them. Several of Sahadevan’s colleagues have embraced technology and encourage students to bring their own devices to school to engage in online learning. But in large classes with multiple students using devices, Sahadevan says it can be hard to monitor everyone.

Some educators worry that teachers haven’t been sufficiently trained to integrate video games into schools. “I’d love you to talk about the kinds of professional development that teachers are going to need,” said Anne Bryant, executive director of the National School Boards Association during the panel. “Where is it going to happen and how is it going to happen?” Her comment echoed the findings of a recent LEAD Commission poll, which reported that many teachers aren’t prepared to use technology effectively.

And while video games may be the future of digital learning, teacher Sahadevan says there are still basic issues that need to be fixed in education before more teachers will utilize technology. “We can’t get books in classrooms,” Sahadevan said. “Unless they’re going to give all these programs for free, its like dangling candy in front of a kid. We want it, but we can’t get to it, and that’s a problem.”

This post was produced by The Hechinger Report, a non-profit, independent journalism organization housed at Columbia University in New York City.