Traditional classrooms are teacher-centered since they use lecture as the primary mode of instruction.  In this model, a teacher delivers all the instruction, and the students listen.

In a CTL classroom, direct instruction typically lasts only 5-10 minutes at a time.  After the direct instruction is finished, students work together in groups to solve problems.  At that point, the teacher becomes part of the social group, facilitating and encouraging students to work with one another.  Wandering around the room, from group to group, the teacher guides the conversation while also getting an idea about how students are struggling.  This additional formative assessment informs the teacher’s instruction.