The proposed work is based on the assumption that there exist a common set of change principles that cut across different orientations to therapy, and that these may be found at a level of abstraction somewhere between the specific clinical procedures used, and the theoretical constructs that have been put forth for explaining why these procedures are likely to be effective. In order to develop a code that could be reliably scored by observers, process researchers have traditionally focused on the detailed events of therapeutic sessions. Such details, however, may vary in degree of therapeutic significance, and are often unique to a particular orientation. In the present research, the goal is to develop a hierarchically-arranged taxonomy of principals of therapeutic feedback, so as to account not only for the specific methods unique to a given session or therapeutic school, but also the higher-order principles that may be common to all orientations. The classification system, which will be described in the vernacular so as to be relevant to different theoretical orientations, will employ numerical taxonomy procedures. Specifically, significant therapeutic events will be sampled from 150 experienced and well-qualified therapists. The clinical vignettes will reflect the therapist's use of feedback for purposes of facilitating clients'/patients' increased awareness. Fifty vignettes each will be sampled from therapists of psychodynamic, behavioral and experiential orientations. Each vignette will be coded with regard to the same set of attributed, and the grouped statistically by means of cluster analysis procedures. It is hoped that the resulting taxonomy of principles of therapeutic feedback revealing areas of agreement across orientations can provide us with potentially functional units of analysis which may be helpful in predicting clinical impact, both within a session as well as ultimate outcome. In addition to producing conceptual units for the development of a transtheoretical process code, agreed-upon principles of therapeutic feedback can have important implications for clinical practice and training. Finally, those principles lower on the hierarchy, that may be unique to a particular orientation, can allow us to identify parameters to be used in future psychotherapy research.