Exploring the Interrelationship Between Sustainability and Quality of Life in Urban Design: A Mixed-Methods Analysis of Shared and Distinct Indicators

Over the past two decades, sustainability and quality of life (QoL) have become foundational concepts in the design of buildings and urban spaces. Due to their strong interrelation and shared emphasis on human well-being, distinguishing between these concepts has proven challenging. While numerous studies have investigated sustainable urban design and QoL, inconsistencies remain: some define QoL as a component of sustainable urbanization, whereas others treat it as a separate construct. This study aims to evaluate and compare both concepts by identifying, weighting, and analyzing their respective indicators, thereby uncovering overlaps, correlations, and distinctions. In particular, it assesses the significance of each indicator within the three dimensions of sustainable urban design: environmental, social, and economic. A mixed-methods approach was employed, beginning with an in-depth literature review and comparative analysis of leading global studies, ranked cities, and official rating systems developed primarily in developed countries. Subsequently, a multi-criteria decision-making (MCDM) method was applied to quantify the importance of each indicator and evaluate their alignment with the three dimensions of sustainability. The results reveal that sustainable urban design comprises 31 indicators, while QoL includes 27, with 19 indicators shared between the two concepts. All identified indicators are distributed across the three core dimensions of sustainability. Specifically, the environmental dimension encompasses 15 indicators for sustainable urban design, accounting for 57.7% of total significance, whereas QoL comprises 10 indicators in this category, contributing 35.67%. In the social dimension, sustainable urban design incorporates 14 indicators (34.82%), while QoL places even greater emphasis here with 15 indicators, representing 54.42%. The economic dimension includes 2 indicators for each concept, contributing 7.43% in sustainable urban design and 9.92% in QoL. These findings underscore that QoL serves as a critical component in the assessment and design of sustainable urban spaces, not only influencing other indicators but also reinforcing aspects—particularly in the social dimension—that are often underrepresented in existing sustainability frameworks. Additionally, the advancement of urban sustainability plays a pivotal role in achieving and enhancing QoL, suggesting a mutually reinforcing relationship between the two constructs.