The Social Interactive Coding System was designed to describe the continuous verbal interactions of preschool children as a function of play areas, addressees, script codes, and play levels. The targeted verbal dimension is assertiveness/responsiveness, indexed by initiations versus responses for conversational turns. SICS can be completed in a minimum amount of time, without access to special equipment or time-consuming transcription. It provides a helpful supplement to conventional communication assessment tools, for the purposes of determining treatment goals, describing baseline and treatment progress.