An equal excess model of coalition formation

Current theories of coalition formation in decision processes of systems at the level of the group lack generality in that some theories do not predict which coalitions are likely to form while others make predictions in only a narrow range of conditions. A model of coalition formation is proposed which predicts coalition formation in a variety of situations. Comparisons between predicted and observed results of studies using different coalition paradigms show considerable empirical support for the model. Despite some ambiguity in specifying the effects of some situational variables, the model provides a framework with which to study the processes of coalition formation and to examine the effects of such situational factors.