by Keiichi Satoh, Antti Gronow & Tuomas Ylä-Anttila
Often the first step to finding a solution is knowing what the problem is.
In April 2018, Antti Gronow, Tuomas Ylä-Anttila and Keiichi Satoh were attending the Joint Sessions of the European Consortium for Political Research (ECPR) in Nicosia, Cyprus. The session in question was organized by Chris Weible, Karin Ingold and Daniel Nohrstedt and it made Gronow and Ylä-Anttila think of how problematic it is to study advocacy coalitions in a comparative context. Coalitions among political actors are central to politics and policy, which is a fact long recognized within the Advocacy Coalition Framework (ACF).
In Cyprus, Gronow and Ylä-Anttila realized that previous research lacks a consistent way of identifying and measuring advocacy coalitions. During a break in the sessions, Gronow and Ylä-Anttila shared their concerns regarding the lack of a consistent method for identifying advocacy coalitions with Keiichi Satoh. Three months later, inspired by a figure explaining the fuzzy sets used in the qualitative comparative analysis, Satoh showed an initial sketch of a way to identify coalitions to Gronow and Ylä-Anttila. After intensive discussions, this sketch evolved into the Advocacy Coalition Index (ACI).
How does the ACI work?
The ACI is a combined measure of policy beliefs and coordination of action, based on techniques of social network analysis. It is a standardized method for identifying and analyzing advocacy coalitions that can be applied to comparative research and also to other research contexts involving attribute and relational data.
To use the index, researchers must first obtain information about policy actors’ beliefs and coordination relationships between these actors. Such data can be collected through a survey, public statements, or any reliable method of data collection. Next, the method focuses on identifying homophilous ties (in which like-minded actors coordinate with one another), cross-coalition ties (coordination between actors holding diverging beliefs), and missing ties (ties that do not exist between like-minded actors). The ACI can be expressed as a formula in the following way:
ACI= 1 – (Cross-coalition ties + Missing ties)
Political subsystems with typical, adversarial advocacy coalitions are likely to be closer to the value of one as a result of the calculation. In addition, to characterize different kinds of advocacy coalitions within subsystems, scholars can analyze variation in the homophilous ties score and in the ratio of cross-coalition ties and homophilous ties (the CCH ratio), as illustrated in the figure below. For example, in the case of adversarial coalitions (i.e. typical advocacy coalitions), there are many homophilous ties between like-minded actors (i.e., few “missing ties”), and almost no ties between actors with dissimilar beliefs.

The ACI can be applied in many different contexts in a consistent way. A standard way of measuring advocacy coalitions thus allows scholars to compare their results with studies conducted in other countries or other policy subsystems.
Our work also has implications outside academia. Policymakers and analysts now have a tool to reliably detect coalitions involved in policy processes, which helps in designing policy proposals that are politically feasible. Policy can be designed, implemented, and evaluated with a clearer understanding of the kinds of coalitions that are involved, as long as appropriate data exists.
We are confident that our systematic, data-driven approach will be a useful contribution to the field of public policy research. We also hope that the ACI will be used as a tool in the policy process.
You can read the original article in Policy Studies Journal at
Satoh, K., Gronow, A. and Ylä-Anttila, T. 2023. “The Advocacy Coalition Index: A new approach for identifying advocacy coalitions.” Policy Studies Journal 51: 187–207. https://doi.org/10.1111/psj.12450
About the Authors
Keiichi Satoh is an Assistant Professor at the Faculty of Social Sciences, Hitotsubashi University, Japan. His research interests include climate and energy policy, social movements, and political processes using network theory and methods. His research has appeared in peer-reviewed journals such as Social Movement Studies, Urban Studies, and Journal of Comparative Policy Analysis.
Antti Gronow is a Senior Researcher at the Faculty of Social Sciences, University of Helsinki. His research interests include climate policy, advocacy coalitions, social network analysis, and political polarization. His research has been published in peer-reviewed journals such as Global Environmental Change, Governance, Policy Studies Journal, Public Administration, and JPART. Follow him on X: @AnttiGronow
Tuomas Ylä-Anttila is an Associate Professor of Political Science at the University of Helsinki. He currently leads four research projects on policy networks, communication networks and climate change politics, and chairs the 14-country comparative research effort Comparing Climate Change Policy Networks (see compon.org). His work has appeared in journals such as Global Environmental Change, Public Administration, Policy Studies Journal, Governance, and British Journal of Sociology.