It is important that you understand the developmental stages for children at both grade levels. A teacher should not try to change too many things at once. It helps to choose an area of strength and build on it. Many times parents are glad to see their kids involved with the same teacher for two years. They often times feel like it might be possible to work as a team with the teacher as far as meeting the needs of the child.
Parents tend to become more involved which has a profoundly positive effect.
Looping allows teachers and parents to set up programs over two years. It helps the parents, children, and teacher to get to know each other and feel comfortable around one another. This helps the educational process in many instances. That is the most desirable solution. In cases where these parents and the teachers can't get along, their is often times and opt-out option where these kid's parents have the option of keeping their child out of the looping system.