This longitudinal experiment investigated the efficiency, effectiveness and group member perceptions of dialectical inquiry (DI) and constructive consensus (CC) approaches to strategic decision making in an asynchronous (distributed) computer-mediated-communications (CMC) environment. There were no differences between DI and CC groups in terms of decision effectiveness. DI groups required significantly more asynchronous meeting time to complete their recommendations and had higher perceived depth of evaluation than CC groups. CC groups reported greater decision acceptance and willingness to work together again than DI groups. Relatively few experiential effects were observed. The results are discussed in terms of their implications for group support systems research and design.