Abstract
In addition to relevant and reliable data, sustainability governance depends on the ability of the data to foster shared understanding. Drawing on critical data studies, this study investigates the process of sensemaking embedded in the data practises of digital citizen science (CS), focusing on the Finnish platform Lake-Sea Wiki. Originally developed in response to citizen initiatives and maintained by a research institute responsible for official national water monitoring, the platform integrates data on water bodies from both citizen observers and authorities. Through qualitative analysis of two surveys and a workshop for citizen observers and water monitoring experts, as well as media content and collaborative observations, the study investigates how actors involved in water monitoring perceive the meanings and usability of CS and the data it produces. The results indicate that the case information system fosters communication among actors, but mostly indirectly, limiting the development of shared understanding. A central inconsistency in sensemaking lies in experts perceiving CS producing more valuable information when citizens are solely involved as observers, whereas active citizen observers emphasise the value of more engaged forms of collaboration, allowing their knowledge of data practises to be utilised. Furthermore, while significant sources of motivation for citizen observers are internal factors, such as benefitting scientific understanding and environmental decision-making, experts rely on external means of motivation. This study highlights the need for transparent, inclusive, and context-sensitive formulation of data practises to enhance the quality, usability, and actionability of CS.