“Social innovation is a contested concept with multiple meanings that have implications beyond academia” (Ayob et al., 2016, p. 1). Since the global economic crisis of 2008, the European Union policies and programmes increased their focus on social issues. Subsequently promoted by the European political agenda (Hubert, 2010), social innovation has become a norm in public policy on social issues. In addition, social innovation is also a fast-growing field of research. Academics dated the present use of the term back to the 1970s and the revolutionary context of the post-1968 student movements, when it stood for a more democratic way of engaging with problems such as social exclusion, lack of wellbeing, deprivation and alienation (Chambon et al., 1982; Moulaert et al., 2010, 2013). As an alternative to dysfunctional and cumbersome existing top-down mechanisms, social innovation meant more bottom-up, community-based, participative and creative ways of addressing social problems. From this perspective, social innovation is still marked at present by the values of social movements, such as emancipation and recognition of the equality of rights between people. It aims for transformative impact on dominant social structures and decision-making.

However, since the 1970s, social innovation progressively lost its revolutionary dimensions, and became a buzzword, as it was used extensively in both policy and research. At present, a single definition cannot encompass the inflation of agendas and of collective actions under this umbrella term. According to a broad approach, social innovation consists of “new ideas that meet unmet needs” (Mulgan, 2019), or of creative solutions to social problems that challenge established or institutional practices. This wide understanding opens the way to cross-fertilisation with fields where innovation processes are more established, such as economic and socio-technical innovation (Baregheh et al., 2009). Thus from a multi-disciplinary perspective, social innovation stands for the introduction of new products, services and processes that change the established way of doing things in the social field (Raynor, 2019; Westley et al., 2014), such as more efficient and more cost-effective procedures. The main difference that makes social innovation stand out from innovative practices in other areas is the combination of both a social focus and a social scope: “innovations that are social both in their ends and their means. New ideas that aim simultaneously to meet socially recognized needs and to create new relationships that enhance society’s capacity to act” (Mulgan, 2019).

Nevertheless, certain social innovation scholars have deplored the dominance of “economic and technologist interpretations and applications of innovation” and of a managerial understanding that is reductionist, over-simplistic and promotes the autocracy of best practices (Moulaert et al., 2013, pp. 13, 18). Therefore, they felt the need to develop a critical stance, considering that in dominant innovation and development agendas, market principles take precedence over non-commercial outcomes, such as empowerment, emancipation and the reconfiguration of power relations. For them social innovation “refers to an ethical position of social justice” and its essence still lies in its transformative outcomes in terms of improving social relations at different levels, from micro relations between people to structures of governance, through empowerment and involvement in decision-making processes (Moulaert et al., 2013, pp. 16–17). From this perspective, social innovation research, should be considered as an analytical concept and as an objective itself. This perspective opens the way to a whole field of transdisciplinary research that explores knowledge production between research and action (Novy et al., 2013).

The two perspectives on social innovation outlined above, the social justice oriented one and the managerial one, reflect, on one hand, a transformative orientation and, on the other, a functional orientation (Laville et al., 2014). The transformative perspective looks at collective actions from the prism of promoting alternative practices, progressive values towards empowerment and social justice (Vicari Haddock & Tornaghi, 2013), whereas the functional focuses on the mechanisms of an alternative provision of goods, processes and services, considered as a remedy for public failures in the social field. Therefore, the functional approach focuses on “social business” and its pragmatic approach to integrating the market economy, with a management-based logic that uses social innovation as a way to create new markets, competitive advantages and new business opportunities (Laville et al., 2014).

The two approaches are also present in the field of housing studies. The functionalist one addresses particularly the topics of social services and social integration related to access to housing, with a focus on the roles of citizens and of civic organizations, strongly linked and fuelled by values of social movements (Vicari Haddock & Tornaghi, 2013). These endeavours contain a criticism from a transformative perspective about the privatization of services and of the rolling-back of the welfare state from social policies, embedded in the understanding of social innovation as a way to modernize welfare services provision by involving the private and third sector and by diminishing public funding (Martinelli, 2013). It also designates social services around housing, directed towards vulnerable groups in society or the homeless, or production-consumption practices related to housing management (Marchesi & Tweed, 2021).

Even if the functionalist approach described above is well suited for the analysis of the new forms of provision of sustainable and affordable housing, in housing studies the term of social innovation is very seldom used in relation to housing production. It is replaced by “social enterprise” for naming the use of non-governmental, market-based approaches for the production of social and affordable housing (Czischke et al., 2012). Social enterprise is at the heart of the change in the profile of affordable housing providers who moved away from the public sphere and integrated resources and skills from the market and community. A whole area of housing literature focuses on the large diversity of social purpose organisations, third sector actors operating on a non-profit distribution basis and providing affordable housing in different national contexts. The dominant perspective for characterising this diversity has been “hybridity” and “hybridisation” of organizational forms, encompassing characteristics of public, market and civil society in varying combinations (Mullins et al., 2012; Smith, 2010). The few cases that use social innovation as an entry point for analysis, do so when they focus on the processes of resources assemblage, scaling-up and scaling-out of pilot projects that introduce alternative housing solutions especially in the area of combatting homelessness (Raynor, 2019).

While the scientific literature has made few links between the scientific concept of social innovation and housing production, there is a strong connection between social innovation and the territorial dimension of housing (MacCallum et al., 2009; Moulaert et al., 2010). European policies have played a pivotal role in connecting social innovation to urban regeneration efforts, particularly through the European Commission's urban area-based programmes of the 1990s and 2000s, such as the Urban Pilot Projects and Urban programmes, which promoted an integrated approach to urban development and area-based interventions. These neighbourhood-centred development policies built on the potential of local communities to support development and local improvement projects, with an endogenous drive. Subsequently, researchers in urban planning have taken on board the concept of social innovation in order to analyse governance outcomes of urban development and the configuration of arenas of participation for local citizen organizations in urban decision-making processes (Healey, 2007).