Participation in advocacy coalitions is one important mechanism through which individuals and organizations may pool their resources and, collectively, become influential in the policy process. Advocacy coalitions are therefore a critical theoretical concept in research on the policy process and political science in general. And yet, there is relatively little agreement on how this concept is best operationalized and measured: How does one empirically detect coalitions, describe their structure, and enumerate coalition membership? To answer this question, we demonstrate the strength of a relational approach and measures of social network analysis, not only to detect clusters of actors that coordinate actions. We also and predominantly emphasize shared beliefs as relational construct in our analysis. We compare cases from Switzerland and the US and conclude that the most robust identification for advocacy coalitions is given if both, belief homophily and within-coalition coordination are detected.
