This article describes a new construct for coding the social communicative performance of school-aged children as they interact with peers and teachers in the classroom. The Social Communication Coding System (SCCS) allows clinicians a way of describing how children actually spend their time during the school day by observing ongoing behaviors that cluster together to describe manner of performance, called behavioral dimensions. The SCCS construct highlights the significance of duration, as well as frequency, of occurrence for gaining a comprehensive view of children's verbal and nonverbal social communication performance during classroom activities. A case example is provided to illustrate the value of observing and categorizing performance based on dimensions, and the importance of considering duration when conducting assessment and planning intervention for children with problematic social communication. (Contains 3 tables and 2 figures.)