1. Introduction
Urban happiness has increasingly become an interdisciplinary concern in urban design and environmental psychology. This study therefore examined how urban-design components relate to happiness in two structurally different neighborhoods of Qom, Iran: Bajak II, a gradually developed and semi-traditional neighborhood, and Pardisan, a newer, planned, and peripheral neighborhood. The study examined which urban-design components are more strongly associated with happiness in each neighborhood; how the relative importance and structural weight of these components differ; and how differences in the physical and social characteristics of the two contexts correspond to these patterns.

2. Literature Review
The study conceptualized happiness as a multidimensional outcome produced through the interaction of three systems: physical design, social interaction, and environmental perception. Ten urban-design components were selected: mobility, transportation and accessibility; security and safety; environmental quality and green space; walkability and cycling; functional diversity and neighborhood services; social interaction and civic participation; third places and happiness-making spaces; presence and spatial dynamism; environmental perception and aesthetics; and sense of belonging and neighborhood satisfaction. The framework emphasized that these components should not be understood as isolated predictors. Rather, happiness was associated with their effective overlap and interaction at the neighborhood scale.

3. Methodology
The research was applied in purpose and quantitative in approach, using a comparative-analytical survey design. Based on Cochran’s formula, 400 respondents were selected from each neighborhood, yielding a total sample of 800. A combination of cluster and simple random sampling was used. Data were collected through a researcher-developed questionnaire containing demographic questions and 30 items, with three items assigned to each of the ten components, measured on a five-point Likert scale. Internal consistency was assessed using Cronbach’s alpha, with coefficients of 0.891 for Bajak II and 0.749 for Pardisan. Spearman correlation analysis was used to assess the strength and direction of associations between the ten components and happiness. Exploratory factor analysis with Varimax rotation identified the underlying structure of the indicators, while separate multiple regression models estimated the relative contribution of each component to happiness.

4. Results & Discussion
The Spearman results revealed substantially different association patterns. In Bajak II, presence and spatial dynamism had the strongest correlation with happiness (r = 0.826), followed by functional diversity and neighborhood services (r = 0.814), and walkability and cycling (r = 0.810). Environmental perception and aesthetics (r = 0.760), social interaction and civic participation (r = 0.762), third places and happiness-making spaces (r = 0.748), belonging and neighborhood satisfaction (r = 0.759), security and safety (r = 0.713), and environmental quality and green space (r = 0.639) showed positive associations. Mobility, transportation and accessibility had the weakest association (r = 0.273). In Pardisan, security and safety had the strongest correlation (r = 0.630), followed by social interaction and civic participation (r = 0.585), whereas belonging and neighborhood satisfaction had the weakest correlation (r = 0.352).
Exploratory factor analysis further demonstrated different structural configurations. Bajak II produced six factors explaining 59.263% of total variance. The first factor combined social relations, neighborhood services, vitality, presence, satisfaction, belonging, and related everyday environmental qualities, indicating a relatively integrated social-functional structure. Pardisan produced ten factors explaining 59.592% of total variance. The first factor emphasized social interaction, women’s security, children’s play safety, participation, neighborhood happiness, child presence, and satisfaction, while other factors grouped lighting and green-space conditions, third-place spaces, daily services and aesthetics, mobility and parking, children’s recreation, neighborhood support and vitality, walkability, pavement quality, and furniture, green space, and nighttime safety. Two items (satisfaction with the quantity and quality of public transportation and neighborhood cleanliness) did not achieve acceptable factor loadings in Pardisan.
Regression results showed a different hierarchy. In Bajak II, the highest standardized beta coefficients were environmental perception and aesthetics (β = 0.178), environmental quality and green space (β = 0.156), and walkability and cycling (β = 0.151); the lowest were belonging and neighborhood satisfaction (β = 0.124) and mobility, transportation and accessibility (β = 0.102). In Pardisan, the highest coefficients were environmental quality and green space (β = 0.198), walkability and cycling (β = 0.193), and presence and spatial dynamism (β = 0.192), while the lowest were functional diversity and neighborhood services (β = 0.163) and belonging and neighborhood satisfaction (β = 0.131).

5. Conclusion
The findings demonstrated that the relationship between urban design and happiness is context-dependent rather than uniform. These findings provided a context-sensitive basis for neighborhood design. Bajak II exhibited a predominantly social-functional pattern and a more integrated factor structure, in which everyday services, social relations, vitality, and environmental qualities are closely interconnected. Pardisan showed a security-social pattern, together with a more differentiated factor structure in which physical and social needs appear as more distinct dimensions. The regression findings additionally indicated that aesthetic and environmental qualities have greater weight in Bajak II, whereas green-space quality and walkability have greater weight in Pardisan. Accordingly, urban-design interventions should be context-sensitive: in Pardisan, priority should be given to improving green-space quality, pedestrian continuity, lighting, perceived security, and small semi-public or third-place spaces that can support interaction. In Bajak II, priority should be given to preserving and improving environmental aesthetics, upgrading minor physical infrastructure, and maintaining functional diversity and social vitality. Overall, happiness cannot be explained by a single universal combination of urban-design factors; rather, its spatial determinants are shaped by the specific physical and social logic of each neighborhood.