Social sustainability metrics: A critical synthesis of selected studies across different urban settings

Social sustainability remains the least consistently defined and measured pillar of urban development, limiting comparability across studies and constraining evidence-based policy. This paper addressed this gap through a systematic analysis of twenty academic frameworks, consolidating 365 extracted metrics into a Holistic Social Sustainability Assessment Framework (HSSF) comprising 147 specialized metrics organized across four domains and seventeen subdomains. Using HSSF as a benchmark, the frameworks were evaluated along two complementary dimensions: spread and density. The findings revealed pronounced fragmentation, with 84% of the specialized metrics appearing in only one or two tools, indicating limited consensus on the core components of social sustainability. Methodologically, the field relied heavily on subjective inputs, with approximately 85% of the metrics classified as subjective, while only 5% were objective and verifiable. Although several frameworks appeared comprehensive at the domain level ten out of twenty covered all four domains coverage was consistently weak at the subdomain level, where no framework exceeded 60% coverage and substantial portions remained unmeasured, with zero-metric subdomains ranging from 41% to 88%. Metric density was similarly uneven, with detailed assessment concentrated in a small number of attributes, while entire domains were omitted in up to half of the reviewed frameworks. These results indicate that existing tools frequently operationalize divergent constructs and are therefore not directly comparable. The HSSF, together with the proposed diagnostic coverage-analysis approach, provides a foundation for developing a more standardized, balanced, and globally applicable set of social sustainability metrics capable of supporting robust assessment and evidence-informed urban policy.