**Preface to "Efficiency, Fairness and Sustainability in Social Housing Policy and Projects"**

The provision of affordable housing for low-income households is a very complex issue that has long been debated in many countries around the world. Social housing (SH) is one of the tools for achieving fairness, social sustainability, and economic feasibility, and it is interrelated with politics, ethics, and economics, as well as the environment, architecture, and technology. In other words, national and local policies, as well as public and private financial resources, are needed to provide SH.

SH also involves social and urban transformations and is, consequently, linked to urban planning and redevelopment projects, real estate market dynamics, and cooperation between public and private stakeholders. Furthermore, decision-making on SH policies and projects has to be supported by assessments of economic feasibility and social and environmental sustainability.

This volume presents studies on various topics to recompose the multi-faceted subjects of social housing within a unified framework.

To provide affordable housing, SH projects have to achieve efficiency and economic feasibility while meeting several constraints, so the trade-off between the price of developable areas and housing affordability is a very common problem in many cities. A study conducted in northeastern Italy proposes a financial model to achieve both social and economic goals through various scenarios and variables, such as the cost of construction work and household income. Other projects must resolve the trade-off between maximizing SH share and minimizing public financial contribution in public–private partnerships (PPPs). An evaluation model can support the decision-making process of urban regeneration projects by also considering economic constraints, such as local real estate market prices and financial feasibility for the developer.

Social housing projects aim to achieve greater fairness, although public regulations can sometimes cause negative effects. To achieve the goal of social sustainability, SH rents must be below market rents and low enough to be affordable for low-income households. A study examines, for example, an Italian law that sets the rent of SH units according to benchmark rents based on local agreements between landlords and renters' associations. The results show that this rule generates significant inequalities and spatial asymmetries within and between cities.

To facilitate economic development, urban planning promotes the construction of road infrastructure, but these projects result in negative social effects when citizens are forced to relocate. A group of researchers proposes a multi-parameter model to assess fair compensation and indemnification and to ensure social protection and financial support for owners and tenants affected by the expropriation of their housing units.

Another relevant issue connected to SH concerns outward regeneration effects in neighborhood-based projects. One study focuses on a conceptual framework useful for qualitative analysis to evaluate future urban regeneration projects, such as public housing districts, that induce environmental and quality-of-life improvements in a broader urban context.

SH is also deeply related to the Sustainable Development Goals (SDGs), although the social dimension of sustainability has been insufficiently explored. To support the creation of inclusive cities and communities, urban projects should be based strictly on social needs. One paper proposes a multi-methodological approach based on combining stakeholder analysis with a particular type of Social Multi-Criteria Evaluation to include the preferences of all stakeholders in the final evaluation.

Other researchers have analyzed how national housing policy or policy strategies can guarantee housing affordability for low-income households. A study conducted in Malaysia identifies multiple reasons why this expected goal has not been met, such as low household incomes; high land prices, construction costs, and compliance costs; mismatch of supply and demand; and ineffective housing planning. Moreover, policy strategies are not always able to translate into affordable housing development and housing affordability for low-income earners, as is the case in Nigeria.

The evolution of social housing policies within the Saudi Arabian context demonstrates that the institutional response in the social housing sector has changed over the years and that in recent times there has been a shift from a public-welfare perspective to a more neoliberal outlook, with the need to adopt specific protocols for working with nongovernmental actors.

Other studies have found that several sociocultural factors influence social housing. Despite the general improvement in housing, according to a study in Mumbai, India, community acceptance of social housing versus slums remain low, due to some related negative effects, such as the change in location and job induced by moving to social housing. In addition, a potential increase in demand for Social Housing may result from the income conditions of some social groups. A survey conducted in South Korea explores the situation of young tenants who live on their own and receive financial support from their parents to pay current housing expenses. It found that a large percentage of young people potentially need this kind of support and that the main explanatory variables are age and income, residential location, and rental deposit. Consequently, the provision of social housing should be expanded to meet young people's need for independent living.

#### **Grazia Napoli and Maria Rosa Trovato** *Editors*
