This document describes the process by which aspects of nonverbal communication that appear to be indicators of involvement were identified, described, classified, and rated. To facilitate this process, an Action Category System was developed through observation in the natural classroom setting and subsequent analyses of the recorded behavior data. Efforts to devise a behavior category system resulted in these final action categories: motion, stance, pause, visual, nonvisual facial, and self-sounds. Dimensions, indications of how a nonverbal activity is performed, were also defined to aid data collection. Dimensions indicate the speed, frequency, duration, directionality, tension, and range of a nonverbal action. To rate these dimensions, a point of reference must necessarily be identified (five bases, or points of reference, for rating dimensions are given and examples of their use). Some recommended instructions for rating each dimension and an alternative proposal for grouping and defining bases are presented. Further explanations of these data collection processes can be found in two of the appendixes which contain a working paper on dimension definitions and coding procedures and a set of data collection exercises. (SDH)