Collective Action Dilemma in Data Sharing for Transboundary Rivers:A Case Study of Mekong River Basin

[Objective] Data sharing serves as the foundation and guarantee for transboundary river cooperation, and its effectiveness largely depends on the degree of support from the external institutional environment. This study aims to address the current gap in research on transboundary river data sharing and provide theoretical support for the ongoing water resources data sharing under Lancang-Mekong cooperation led by China. [Methods] Based on the institutional collective action (ICA) framework, this study revealed the mechanisms through which structural external environments influenced cooperation risks. Furthermore, utilizing this framework, the study analyzed the characteristics of the external environment for data sharing within the Mekong River Commission (MRC), the structure of cooperation risks faced by participating parties, and the impact of these risks on data sharing behaviors and outcomes. [Results] (1) The data sharing system of the MRC was characterized by weak authorization relationships, multiple and complex tasks, and high heterogeneity in the preferences of the participating parties. (2) Cooperation risk was the core driver of the collective action dilemma in data sharing. Different data-sharing tasks are subject to various types of collaboration risks. (3) The decentralization reform of the MRC increased cooperation risks and further decreased the effectiveness of data sharing. [Conclusion] Based on the findings, it is recommended that future data sharing under the Lancang-Mekong water resources cooperation should: (1) begin with relatively simple tasks that involve low cooperation risks, focusing on low-risk, high-consensus tasks to advance data sharing progressively; (2) adhere to the principle of “software before hardware,” prioritizing soft infrastructure development tasks such as unifying monitoring standards, enhancing data management capabilities, and coordinating perceptions on sharing, and then gradually transition to constructing a unified data cooperation platform and a cross-border station network system; and (3) fully consider the compatibility between cooperation benefits and transaction costs, adopt a bottom-up institution construction model, promote the implementation of data sharing tasks through the approach of “pilot projects first, item-by-item negotiation,” and gradually construct a data sharing institutional framework for the entire river basin.