This paper is an account of the theoretical and practical underpinnings of the Decision-Proposal Modification Coding System (DPM), which allows researchers to study more accurately the many aspects of group decision making in organizations. Following an introduction that reviews and supports arguments for process-oriented research on decision making, several conclusions of past research on decision making are summarized. Other sections of the report contain discussions of the following topics: (1) the situation and content of organizational decision making, (2) the use of role theory to support the perspective for creating the coding system, (3) the sequences in the process of negotiating decisions, (4) a multilevel model of decision making, (5) the eight assumptions underlying development of the DPM, and (6) the criteria for categorizing organizational communication with the coding system. The codes and their definitions are attached. (RL)