"We have not had one single issue with bullying — maybe it's because they look after each other, but we have not had problems like that at all," said Judy Farris, principal at Navigator Pointe Academy, a charter school in West Jordan.

Brandenburger said he uses the age gap to give his older students a sense of social responsibility at school.

"The older students are examples and we kind of hold that over their heads a little bit," Brandenburger said. "We hold them accountable for their behavior and they do know that little people are watching."

He said teachers use the age dichotomy to benefit both older and younger students, such as pairing them up with reading buddies to help the younger students learn to read.

"A lot more opportunity arises for our younger children because we have the older kids here and the older kids get the experience of helping people," Brandenburger said. "They learn the community relies on all the people as being an active part of it."

Grant Beckwith, principal at American Heritage, a K-8 school in American Fork, said having younger students around helps the older ones mature faster.

"On the other side of the coin people will level the charge eighth-graders are much different than first-graders — yes, but at the same time the older ones learn to look out for the younger ones; they get the feeling of being the 'adults' in the school and they tend to mature faster."

Even so, some leaders say at their K-8 schools the younger and older students barely see each other. They are in different wings of the building, with a different lunch schedule — not unlike plans Salt Lake has proposed.

Under the proposed model, kindergartners through fifth-graders would remain in self-contained classrooms. Older students would have access to a variety of different courses and electives just like a normal middle school, while remaining in the elementary environment.

The lack of opportunities in a small elementary school as opposed to a big middle school has been a big concern for parents in Salt Lake district.

K-8 leaders admit they can't offer such things as large music programs or numerous clubs. But they say because of the small setting students have a greater opportunity for involvement.

Plus they are in an environment for nine years where they are well-known by the teachers, who understand their needs and their strengths, said Clarke.

"At that point teachers have been able to pick up on what a student's special abilities, talents and interests are and they can build on those things," Clarke said. "They can help nurture those interests and those talents and they can help them to feel good about themselves."

Probably the biggest advantage, K-8 leaders say, is that students have one less transition.