A taxonomy of localized sustainable development goal indicators: Mapping progress, gaps, fragmented monitoring, and priorities in urban SDG localization

Cities worldwide are endeavoring to adapt the Sustainable Development Goals (SDGs) to their local contexts to ensure their effective implementation. The diversity among cities highlights their varied experiences, resulting in a wide array of localized indicators documented in the literature. These variations in indicators have led to complexities and fragmentation in monitoring and assessment across different cities, thereby complicating global comparisons. To address this issue, we propose a taxonomy that systematically organizes localized SDG indicators. This taxonomy enables the identification of strengths, gaps, and limitations in current indicator frameworks, supporting the enhancement of localized SDG monitoring and implementation. Using systematic review and deductive content analysis, 431 localized indicators were identified from 57 peer-reviewed studies published between 2015 and 2023. The findings indicated that approximately 49.7% of the SDG targets were directly aligned with various localized indicators, whereas 50.3% of the targets lacked corresponding indicators, revealing significant implementation gaps. Furthermore, 36.1% of the targets were associated with multiple indicators, underscoring the need to prioritize targets and to address the issue of overlapping indicators, which can complicate effective monitoring and resource allocation. The distribution of indicators was also uneven across sectors and sustainability dimensions, with a pronounced focus on environmental and social dimensions, highlighting imbalances in indicator types. This taxonomy offers a structured tool for policymakers, urban planners, local governments, and researchers to identify gaps in their SDG implementation, enhance comparability, prioritize underrepresented targets, and fortify localized SDG implementation.