Copyright © 2019 by the author(s). Published here under license by the Resilience Alliance. Fischer, M., M. Nguyen, and L. Strande. 2019. Context matters: horizontal and hierarchical network governance structures in Vietnam’s sanitation sector. Ecology and Society 24(3):17. https://doi.org/10.5751/ES-11036-240317 Research, part of a Special Feature on Collaboration and conflicts in complex water governance systems across a development gradient Context matters: horizontal and hierarchical network governance structures in Vietnam’s sanitation sector Manuel Fischer 1,2 , Mi Nguyen 3 and Linda Strande 1 ABSTRACT. Governance networks describe the complex relations among different types of actors involved in the governance of a policy issue. Here, we ask how different institutional and socioeconomic contextual conditions influence the structure of these networks and result in more horizontal or hierarchical types of governance networks. To answer this question, we study Vietnam’s sanitation sector and compare two different provinces, Hanoi and Ben Tre. More specifically, we analyze networks of information exchange among key actors based on face-to-face interviews and prestructured questionnaires. We find that in the highly urbanized capital city of Hanoi, which serves as a national leader of innovation, where national and international actors are present, and where local actors have high capacities, information exchange tends to follow horizontal network structures. In the more rural, typical province of Ben Tre, hierarchical structures dominate. Key Words: hierarchical network structures; horizontal network structures; information exchange; network governance; sanitation; Vietnam INTRODUCTION Dealing with complex policy issues such as those related to the management and development of the sanitation sector in non- Western countries requires forms of governance that foster interaction and collaboration among actors from different levels of government, from the local to the international level, from different interdependent issue sectors, as well as actors from government, the private sector, and research institutions. The governance network perspective emphasizes the interrelations of the many different actors involved in a given policy sector. The structure of these governance networks depends on the institutional and socioeconomic context in which they are situated (Lubell et al. 2012, Fischer 2015). We therefore ask how different contextual conditions influence the structure of governance networks and whether they result in more horizontal or more hierarchical types of governance networks. Here, we explore these questions for the specific case of Vietnam. Vietnam is one of three countries that are still formally labeled as socialist regimes (besides China and Laos). While traditionally being organized in a rather centralized way (de Wit 2007), the country has made important efforts toward decentralization and the inclusion of private stakeholders since the 1990s (Wescott 2003, Trung et al. 2015; S. Fritzen, unpublished manuscript: https:// www.researchgate.net/publication/228590861 _The_'foundation_ of_public_administration'_ Decentralization_and_its_ discontents_in_ transitional_Vietnam). We study networks of information exchange among key stakeholders from the sanitation sector in the provinces of Hanoi and Ben Tre. The development of the sanitation sector is an important challenge in contemporary Vietnam, and the sector is an exemplary case of how tendencies for traditional, hierarchical, centralized structures coexist with more horizontal, decentralized structures of governance. Our analysis is based on two types of comparison: within-country and between-country. First, we explicitly compare two provinces in Vietnam where governance networks evolve under different contextual conditions, and where we thus expect to see different governance network structures. Overall, the presence of crucial national and international actors points to stronger state reach in Hanoi; the role of Hanoi as national leader in innovation and development suggests a higher level of development; and the higher pressure from urbanization in Hanoi contrasts with the rural province of Ben Tre. For these reasons, we expect more horizontal types of governance network structures (e.g., information flowing in both directions, depending on actors’ perceptions of challenges, and in a bottom-up way) in Hanoi, and more hierarchical types of governance network structures (e.g., information flowing in one direction only, independently of actors’ perceptions of challenges, and mostly in a top-down way) in Ben Tre. Second, we implicitly compare Vietnamese governance networks to Western governance networks. The data stem from face-to-face interviews based on prestructured questionnaires and are analyzed using the tools of inferential network statistics. Our study makes at least two important contributions to the literature on governance networks, and, more broadly, to the study of governance of complex environmental and societal problems. First, it contributes to the comparative studies of governance networks and the crucial question of how contextual conditions influence these networks (see Mancilla García et al. 2019). Comparative studies of governance networks influenced by different contextual conditions are still rare. Examples of existing comparative governance network studies are those comparing the same policy sector in different countries (Brockhaus et al. 2014), different policy sectors in the same country (Fischer and Sciarini 2016), a single policy sector over time (Ingold and Fischer 2014), or, as here, a single policy sector in different local contexts in the same country. Second, although empirical instances of horizontal governance networks have been observed in democratic countries in Western Europe and North America (Weible 2010, Berardo et al. 2014, Lubell et al. 2014, Scott 2015, Bodin and Nohrstedt 2016, Fischer and Sciarini 2016), less is known about governance networks in other, non-Western contexts (Fischer 2018, Ongaro et al. 2018, Teets 2018). In the Vietnamese context of attempted decentralization and support for private initiatives (Wescott 2003, 1 Eawag, Dübendorf, Switzerland, 2 University of Bern, 3 Nguyen Tat Thanh Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam