Each program is a profile for a group of children with similar age and abilities. Children's placement in a group is primarily determined by age. Other factors considered include social maturity, language development, and approaches to learning. The younger the group of children, the smaller the age range of a classroom. As children grow older, they benefit from multi-age classrooms.

At Canterbury School, each classroom environment is flexible and changes to meet the needs and abilities of the group. Additional learning materials are utilized and the curriculum continues to challenge children as they grow. Therefore, children do not outgrow their classrooms and do not need to move to another classroom based on their birthday. Instead, children move together to the next classroom in small groups during certain times of the year.