Social Innovation: Field Analysis and Gaps for Future Research

Scientific publications on social innovation and interest in the subject have grown substantially in the last decade, evidencing the need for more studies in this direction. This study aimed to map the scientific publications and intellectual structure in the field of social innovation, through a bibliometric study. The bibliometric survey specifically considered the period 2006–2021, through data indexed by the SCOPUS database, which included journals with a high impact factor. A total of 1192 articles were analyzed using the software VOSviewer (VOS) 1.6.15, to graphically map the material. The results showed explosive growth in the academic literature on social innovation in the last decade; moreover, they allowed the identification of the main authors, articles, topics, institutions, and countries in the field. From the analyses, a theoretical framework structured with four main emphases (clusters) was evidenced: (1) social entrepreneurship and the third sector; (2) strategic management and innovation; (3) sociopolitical aspects, urban development, and governance; and (4) innovation and sustainability.


Introduction
The business, political, and academic debate on how to maintain or reshape the current economic development model has intensified in recent decades. The clash between economic growth and socio-environmental development has shown the insufficiency of existing structures and policies in solving some of the most pressing issues of today, such as social inequality, health, poverty reduction, and climate change, among other problems that are not yet solvable [1,2].
Debates in this direction have stimulated academics, civil society, governments, and organizations to think under a new paradigm, and thus, in a perspective that goes beyond economic resolutions, hence the demand for innovative initiatives and solutions that prioritize meeting the aforementioned challenges [3].
Social innovation (SI) can be seen as part of the efforts employed, with a view of solving localized social problems and, more recently, systemic and structural issues [4]. The discussion around the theme has been more strongly emphasized in the last decade and, in a way, it has become the rallying cry of many Western academics and political administrations [5][6][7]. More than that, the idea of the social dimension of innovation has become a broad and accepted idea [8], raising expectations in relation to social performance. SI emerges, in this context, as an alternative for solving such problems. Social innovation is understood as the initiatives that seek to solve social problems, and also to promote social transformation, through inclusion, empowerment, participation, and new relationships [1,[9][10][11]. In this sense, it is clear how relevant the study of this innovation model is. It is a systemic and expanded concept of innovation, in which various social agents can be innovators and not just companies [12]. Unlike technological innovations that are driven by market and economic profit [13], this model of innovation (SI) is driven by social concerns and challenges [14].
In order to know how research in this field has evolved, it was decided to carry out a bibliometric survey of publications, between the periods (2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018)(2019)(2020)(2021), in the SCOPUS database. This database was chosen due to the fact that it includes journals with a high impact factor. This article aimed to map the international scientific publications, as well as to identify the intellectual structure of the field, through authors and seminal works, based on bibliometric techniques.
Similar studies have been carried out in the field of social innovation [15][16][17]. In the study by Van der Have and Rubalcaba [15], the authors identified four intellectual communities, based on a broad database, as follows: (1) community psychology, with an emphasis on social change; (2) creativity, with an emphasis on organizational aspects; (3) social challenges, with an emphasis on technologies, sustainability, and entrepreneurship; and (4) local development, with an emphasis on governance, institutions, citizen participation, and empowerment. In the study by Silveira and Zilber [16], the authors identified some main themes addressed in the field, namely social entrepreneurship, public policies, and institutional theory. In the third study [17], Agostini and other authors reinforced the theme of social entrepreneurship, in addition to corporate social responsibility and intersectoral partnerships. Although there are related topics among the studies, the previous studies have not provided an overview of the clusters and theoretical orientations specifically addressed in this research.
This article advances the understanding of scientific publications and intellectual structure in the field of SI by identifying four main clusters and possible theoretical orientations in the areas of social sciences, management, and business. In addition, it brings important contributions by identifying possible gaps for future research, based on bibliometric analysis.

Materials and Methods
The research is characterized as a bibliometric study. Bibliometric research enables the use of indicators to establish a mapping of scientific production in a given field of study [18]. This type of analysis is based on the notion that bibliographic records, including citations, are such indicators, useful in scientific activity [19]. It starts from the premise that the most cited works and authors are those that have greater influence in the field, thus, the greater the frequency, the greater the importance of the subject for the research topic. That is, the more often a given term "co-occurs", the more strongly the works will be related, indicating that they belong to a similar area of research [20].
Bibliometry uses statistical and quantitative analysis to measure scientific production [21]. Authors such as White and McCain [22] have suggested the use of bibliometrics to analyze academic literature, and thus map the structure of knowledge, based on the historical description. Another important contribution of this technique is the representation of well-defined clusters, since the grouping of a theme (from sub-themes, divisions, or groups) allows a more detailed understanding of what is being researched [23]. Statistical data allow you to quantitatively analyze the relevance of a topic (node) or its importance within a set of related variables (network). Graphically, nodes are represented by circles, while edges represent lines connecting these points. Conceptually, nodes can represent people, organizations, keywords, or countries, while edges represent connections in social networks, diverse relationships, or relationships between themes [24,25].
To achieve the proposed objectives of mapping international scientific publications, as well as identifying the intellectual structure of the area, through bibliometric techniques, this research was carried out in five steps: (1) the first stage consisted of choosing the theme to be explored, in this case, social innovation; (2) in the second stage, the database (SCOPUS) and the period to be researched (2006-2021) were defined; (3) in the third stage, the most appropriate search term for the study was defined, using the term "social innovat*" (with an asterisk), in order to consider variations of the expression "social innovation"; (4) the fourth stage consisted of selecting the articles and pre-analysis of the keywords so that there was no divergence with the purpose of the study; (5) and finally, the fifth step consisted of the bibliometric analysis of the terms indexed in the articles.

Data Collection and Analysis Procedures
In view of the exponential increase in publications on social innovation in the last decade, it was decided to carry out a bibliometric survey, with an exploratory-descriptive characteristic, specifically covering the period 2006-2021. The restriction on the time interval was justified due to the concentration of approximately 91% of the total publications in this period. Given the importance of data collection and processing, in using this research technique, data indexed by the SCOPUS database were used, as this included journals with a high impact factor. Figure 1 summarizes the search parameters used. "social innovat*" (with an asterisk), in order to consider variations of the expression "social innovation"; (4) the fourth stage consisted of selecting the articles and pre-analysis of the keywords so that there was no divergence with the purpose of the study; (5) and finally, the fifth step consisted of the bibliometric analysis of the terms indexed in the articles.

Data Collection and Analysis Procedures
In view of the exponential increase in publications on social innovation in the last decade, it was decided to carry out a bibliometric survey, with an exploratory-descriptive characteristic, specifically covering the period 2006-2021. The restriction on the time interval was justified due to the concentration of approximately 91% of the total publications in this period. Given the importance of data collection and processing, in using this research technique, data indexed by the SCOPUS database were used, as this included journals with a high impact factor. Figure 1 summarizes the search parameters used. Data analysis was performed using the VOSviewer software, version 1.6.15. In the searches performed, publications in the area of "Social Science" and "Business, Management, and Accounting" were selected, with information extracted regarding the title, authors, abstract, keywords, year of publication, and bibliographic references. The results were obtained through the following types of analysis: (i) citation analysis-this type of analysis identifies the most cited authors, that is, it considers that the most cited works exert greater influence in the field [23,26]; (ii) co-citation analysis-which identifies potential similarity between pairs, enabling the grouping of articles into clusters, and thus, indicating different lines of thought; (iii) co-occurrence analysis-which analyzes the frequency of keywords, journals, and other factors, allowing the analysis and visualization of a network of words and citations between the respective studies [27,28].

Results
The results described in this article take into account four main analyses. First, advances in social innovation in the literature and citation analysis of the main articles are discussed. Secondly, the co-occurrence of keywords in the articles is examined. The third stage presents the most cited authors, including the co-authorship networks and Data analysis was performed using the VOSviewer software, version 1.6.15. In the searches performed, publications in the area of "Social Science" and "Business, Management, and Accounting" were selected, with information extracted regarding the title, authors, abstract, keywords, year of publication, and bibliographic references. The results were obtained through the following types of analysis: (i) citation analysis-this type of analysis identifies the most cited authors, that is, it considers that the most cited works exert greater influence in the field [23,26]; (ii) co-citation analysis-which identifies potential similarity between pairs, enabling the grouping of articles into clusters, and thus, indicating different lines of thought; (iii) co-occurrence analysis-which analyzes the frequency of keywords, journals, and other factors, allowing the analysis and visualization of a network of words and citations between the respective studies [27,28].

Results
The results described in this article take into account four main analyses. First, advances in social innovation in the literature and citation analysis of the main articles are discussed. Secondly, the co-occurrence of keywords in the articles is examined. The third stage presents the most cited authors, including the co-authorship networks and concentration of study areas, the main journals, and organizations. Finally, the fourth step examines the co-citation of references and bibliographic coupling of authors.

Evolution of Social Innovation in the Literature
One of the first citations related to social innovation appeared in 1970, with the title "Introducing Social Innovation", in The Journal of Applied Behavioral Science [29]. However, more frequent publications on this subject only started in the 1990s, with a more expressive growth from the 2000s onwards. Specifically, in the area of management and business, the results point to an expressive growth of publications in the last 10 years, as shown in Figure 2. examines the co-citation of references and bibliographic coupling of authors.

Evolution of Social Innovation in the Literature
One of the first citations related to social innovation appeared in 1970, with the title "Introducing Social Innovation", in The Journal of Applied Behavioral Science [29]. However, more frequent publications on this subject only started in the 1990s, with a more expressive growth from the 2000s onwards. Specifically, in the area of management and business, the results point to an expressive growth of publications in the last 10 years, as shown in Figure 2. The increase in studies on the subject, in a way, is related to the successive crises that have accompanied the global socioeconomic state, the political state, and the growing social demands of developing economies. Social innovation seeks to contribute with solutions and/or improvements to social problems [4], so this context can be seen as a driving factor in this area of study, or even as a driver in the recognition of social innovation and in the insertion of the theme in corporate, political, and academic agendas.
To identify the most influential works in the field, the 16 articles with the highest number of citations were selected. The number of citations of an article shows not only the quality of the document but the influence and promotion of publication within a research field [30]. Table 1 shows the most cited articles, including authors, journals, and year of publication.  The increase in studies on the subject, in a way, is related to the successive crises that have accompanied the global socioeconomic state, the political state, and the growing social demands of developing economies. Social innovation seeks to contribute with solutions and/or improvements to social problems [4], so this context can be seen as a driving factor in this area of study, or even as a driver in the recognition of social innovation and in the insertion of the theme in corporate, political, and academic agendas.
To identify the most influential works in the field, the 16 articles with the highest number of citations were selected. The number of citations of an article shows not only the quality of the document but the influence and promotion of publication within a research field [30]. Table 1 shows the most cited articles, including authors, journals, and year of publication.
Boons and Ludeke-Freund' article [31] ranked first in the number of citations (856) in the SI area. The article discussed business models for sustainable innovations, and, in this work, the authors related SI to the context of social entrepreneurship, social business, and the base of the pyramid (BoP) strategies. The authors identified three important currents for sustainable innovations, one of them being "social innovation". The second article with the highest number of citations was by Voorburg, Bekkers, and Tummers (649) [32], where the authors presented a systematic literature review, discussing the co-creation and co-production of social innovations in the public sector. Part of the discussions related to the conditions under which co-creation and co-production with citizens take place in public sector innovation processes.
The third most cited article was by Seyfang and Haxeltine (479) [33], in which the authors assessed the role of community-based initiatives (basic social innovations) in the transition to a sustainable economy and in influencing broader sociotechnical social systems. Practical and theoretically grounded recommendations were given in order to promote the spread of such movements beyond their niche. The fourth most cited article was by Cajaiba-Santana (354) [8]. In this study, the author proposed to investigate the field of social innovation, from a conceptual framework, combining the theory of structuring (structure and agency) with institutional theory. Such theoretical approaches, from the author's perspective, contribute to the investigation of social innovation as an engine of social change. The fifth article-by Van Der Have and Rubalcaba (253) [15]-was a bibliometric study on SI, where four main clusters were identified: (1) community psychology, (2) research in creativity, (3) social challenges, (4) and local development. However, it should be noted that the results were based on a wide database. In the present study, in particular, the investigation was limited to the areas of "social science" and "business and management", as we intended to elucidate the studies in this field, specifically.

Co-Occurrence Network of Keywords
The co-occurrence analysis of the most frequent keywords (keywords that appear together in the same article) allows highlighting the most relevant research topics in the SI area. The author's keywords, which appear below the abstract, were considered using the "full counting" method, which assigns the same weight to each co-occurrence link. Out of a total of 1192 publications, the VOSviewer software identified 4547 keywords. Figure 3 represents the 100 keywords with the most frequent co-occurrences, considering a minimum of 10 occurrences. The larger the node and keyword, the greater the weight, indicating the number of articles in which these keywords appeared [34]. Thicker lines indicate a higher frequency of co-occurrence, that is, the number of articles in which the keywords appeared together. The smaller the distance between the nodes, the stronger the relationship between them, indicating the article number where two keywords appeared together, compared to the co-occurrence of other keywords. Node colors indicate that the keywords belong to the same cluster (group of related keywords). Among the most cited keywords was social innovation, with 459 occurrences, followed by the terms social entrepreneurship (88 occurrences), innovation (27), social enterprises (33), sustainability (17), governance (17), and corporate social responsibility (15). These words indicate a strong relationship between the studies and the context of social entrepreneurship and/or social businesses, in addition to innovation, sustainability, governance, and corporate social responsibility. Compared to traditional management literature, such terms may indicate a more sociological focus; however, it is worth mentioning that approaches such as "corporate social responsibility", "social companies", "social entrepreneurship", and "governance", despite the interface between business and society, take into account a more business and strategic perspective, under "win-win" conditions. The colors of nodes and edges indicate that the keywords belong to the same cluster, showing the relationships between the terms. Thus, the closer the terms obtained are to each other, the stronger their relationships will be, in terms of co-occurrence links.
Studies belonging to the green and light blue cluster, for example, are related to terms such as social economy, social capital, social inclusion, rural development, local development, third sector, and urban policy [35][36][37][38]. The red cluster demonstrates a strong relationship between the terms innovation, co-creation, capabilities, participation, empowerment, governance, and public policies [39][40][41][42][43]. The yellow cluster, on the other hand, indicates studies related to sustainable development, climate change, economic and social Among the most cited keywords was social innovation, with 459 occurrences, followed by the terms social entrepreneurship (88 occurrences), innovation (27), social enterprises (33), sustainability (17), governance (17), and corporate social responsibility (15). These words indicate a strong relationship between the studies and the context of social entrepreneurship and/or social businesses, in addition to innovation, sustainability, governance, and corporate social responsibility. Compared to traditional management literature, such terms may indicate a more sociological focus; however, it is worth mentioning that approaches such as "corporate social responsibility", "social companies", "social entrepreneurship", and "governance", despite the interface between business and society, take into account a more business and strategic perspective, under "win-win" conditions. The colors of nodes and edges indicate that the keywords belong to the same cluster, showing the relationships between the terms. Thus, the closer the terms obtained are to each other, the stronger their relationships will be, in terms of co-occurrence links. Studies belonging to the green and light blue cluster, for example, are related to terms such as social economy, social capital, social inclusion, rural development, local development, third sector, and urban policy [35][36][37][38]. The red cluster demonstrates a strong relationship between the terms innovation, co-creation, capabilities, participation, empowerment, governance, and public policies [39][40][41][42][43]. The yellow cluster, on the other hand, indicates studies related to sustainable development, climate change, economic and social effects [33,44,45].
The blue cluster brings together works related to knowledge and learning, education, human aspects, and social change [46][47][48]. Finally, the purple cluster presents studies related to social enterprises, corporate social responsibility, non-profit organizations, and social entrepreneurship [49][50][51]. Table 2 shows the top 10 keywords, including frequency of occurrence and overall link strengths. As seen, the term social innovation had a higher rate of occurrence and strength of connection in relation to the others, as it refers to the search term used in the research and, therefore, connected to all other terms in the database.

Major Journals and Authors Co-Citation Analysis
In this section, the co-citation analysis of the main journals and authors is presented. A co-citation analysis analyzes the simultaneous citation of two items (e.g., article, journal, author) from a third document. This technique groups bibliometric material into clusters, through network analysis, allowing researchers to identify how research, research institutions, and countries are related and structured [20,25], in order to understand the development of a field.
For the analysis of the most cited journals, the analysis of co-citation of sources was used, through the full counting method, having as a parameter a minimum number of 35 citations per source. The size of the demonstration is the number of articles published and the distance between them, i.e., the frequency of citation. Based on the defined parameters, 162 journals were obtained, which were grouped into four clusters, from which some main domains of the field were identified (Figure 4). This analysis allows knowing the structural connections of a field-the proximity, association, and dialogue established between documents and researchers. By analyzing the clusters and journals with the highest number of citations (Figure 4) The red cluster brings together studies related to political and socio-economic aspects, as well as urban, regional, and public management aspects. The blue cluster brings together works in the area of management and strategy. The green cluster brings together works related to social entrepreneurship and the third sector (non-profit organizations), and finally, the yellow cluster brings together studies that permeate the theme of innovation and sustainability. In this sense, these areas have been the basis for a large part of the discussions on social innovation, in the area of management and business. Table 3 shows the 12 journals with the highest citation rate and their respective impact factors.  The red cluster brings together studies related to political and socio-economic aspects, as well as urban, regional, and public management aspects. The blue cluster brings together works in the area of management and strategy. The green cluster brings together works related to social entrepreneurship and the third sector (non-profit organizations), and finally, the yellow cluster brings together studies that permeate the theme of innovation and sustainability. In this sense, these areas have been the basis for a large part of the discussions on social innovation, in the area of management and business. Table 3 shows the 12 journals with the highest citation rate and their respective impact factors. The indices presented reinforce the productivity and impact of the most cited journals, which is an important point for the advancement and consolidation of the field, which is still emerging and under construction. To complement and reinforce the discussion of the identified theoretical domains, an analysis of citation and co-citation of authors was carried out. Thus, to identify a brand of authors in the area, a citation and co-citation analysis was used. This technique allows visualizing the pairs, in this sense, a dialogue between the authors, in addition to enabling the grouping into clusters. A co-citation analysis, for example, indicates that two documents and/or authors appear together in the references of a third document. It is also noteworthy that older publications and their respective authors appear as central because they are cited and co-cited more frequently. Thus, as the field of study is considered emerging, the first ones published become the most referenced.
A total of 53,614 authors were cited, with Moulaert being the most cited author (942 citations), followed by Mulgan (739), Nicholls (359), Howaldt (352), Swyngedouw (313), and Maccallum (273). Figure 5 illustrates the co-citation network between authors, featuring four clusters, and the most cited authors, according to the size of the circle. In order of the number of components, the first cluster is green with 67 authors, the second is blue with 53 authors, the third is red with 34 authors, followed by the yellow cluster with 18 authors. The co-citation map was established with a parameter of a minimum of 50 citations per author and resulted in a total of 174 authors. The indices presented reinforce the productivity and impact of the most cited journals, which is an important point for the advancement and consolidation of the field, which is still emerging and under construction. To complement and reinforce the discussion of the identified theoretical domains, an analysis of citation and co-citation of authors was carried out. Thus, to identify a brand of authors in the area, a citation and co-citation analysis was used. This technique allows visualizing the pairs, in this sense, a dialogue between the authors, in addition to enabling the grouping into clusters. A co-citation analysis, for example, indicates that two documents and/or authors appear together in the references of a third document. It is also noteworthy that older publications and their respective authors appear as central because they are cited and co-cited more frequently. Thus, as the field of study is considered emerging, the first ones published become the most referenced.
A total of 53,614 authors were cited, with Moulaert being the most cited author (942 citations), followed by Mulgan (739), Nicholls (359), Howaldt (352), Swyngedouw (313), and Maccallum (273). Figure 5 illustrates the co-citation network between authors, featuring four clusters, and the most cited authors, according to the size of the circle. In order of the number of components, the first cluster is green with 67 authors, the second is blue with 53 authors, the third is red with 34 authors, followed by the yellow cluster with 18 authors. The co-citation map was established with a parameter of a minimum of 50 citations per author and resulted in a total of 174 authors. Authors who approach the center of the clusters have a close intellectual connection among themselves, most likely because they involve related intellectual efforts and co- Authors who approach the center of the clusters have a close intellectual connection among themselves, most likely because they involve related intellectual efforts and coauthorship in works. The first theoretical discussion group is aimed at social entrepreneurship and the third sector (cluster 1-green), with the focus of citation on Alex Nicholls (359 citations). Among the most cited studies were "Social Innovation: Blurring Boundaries to Reconfigure Markets" [52] and "New Frontiers in Social Innovation Research" [46]. The latter is a book that brings together the participation of other important authors in the area, such as Howaldt (140 citations), Schwarz, Westley, Bouchard, Klein, and Lévesque, who are representatives of different schools and research centers. Another citation focus of this cluster is Johanna Mair (243 citations), with studies related to the context of social entrepreneurship, or social companies, with an emphasis on the study: "Social entrepreneurship research: a source of explanation, prediction, and delight" [53]. Several authors in this cluster addressed the issue of social entrepreneurship and the creation of social value [53][54][55][56]. Recently, Seelo and Mair published the study "Social Innovation: Specifying Pathways for Impact", discussing the role, potential, and consequences of social innovation, based on a procedural and longitudinal analysis of four social companies. The authors shed light on these questions and suggested that research on social innovation, especially related to developing countries, should expand the concept of absorptive capacity.
Cluster 2-blue, on the other hand, involves theoretical discussions and authors whose studies adopted a perspective related to theories of strategic management and innovation. The author with the highest number of citations was Geoff Mulgan (739 citations). Among the author's most cited works were "Social Innovation Theories: Can Theory Catch Up with Practice?" [57] and "The Open Book of Social Innovation", co-authored with Murray [1]. This last work refers to a book that brings together efforts for a better understanding of the concept and scope of social innovation. The authors' discussion appears in a more instrumental and utilitarian way, suggesting stages of social innovation-from its creation to its diffusion-similar to the process that occurs with technological innovations, with the ultimate objective of systemic change. Other authors linked to this cluster are Howaldt (352 citations), Caulier-Grice (260), Schwarz (182), Tucker (173), and Van der Have (93). These authors discussed technological innovation and the connection and interdependence of the processes of both types of innovation-social and technological. The blue cluster shows the authors' connection with some research centers in social innovation, located in Europe and the United States: The Young Foundation (NESTA), Europe Union (TEPSIE), Heidelberg University, Oxford University, and the Center for Social Innovation (Stanford). The authors represent a wide network of studies and theoretical approaches on social innovation, ranging from work oriented to the practice and instrumentalization of innovation, to more theoretical discussions. In this cluster, there is also an approximation of the discussions with the theoretical currents of technological innovation, institutional theory, and innovation systems [1,8,46,58]. It is not by chance that studies in this cluster bring together key authors in their theoretical basis [13,59,60], a reference in innovation.
Cluster 3-red, brings together theoretical discussions involving sociopolitical aspects, urban development; community governance; and territorial, local, and socioeconomic development. The most cited author in this cluster was Frank Moulaert (942 citations), followed by Swyngedouw (313), MacCallum (273), Martinelli (271), Mehmood (251), and Gonzalez (234). As an example, there is the study "Towards Alternative Model(s) of Local Innovation", published in Urban Studies [61]. Another example is the book "Social Innovation and Territorial Development", in which Frank Moulaert appears as the organizer, in co-authorship with Diana MacCallum [62]. Several other publications have demonstrated networks of co-authorship and intellectual connection between authors [9,[63][64][65]. Some of the researchers in this cluster have links with CRISES (Centre de Recherche Sur Les Innovations Sociales), a Research Center in Social Innovation, at the University of Québec, in Montréal. It is an inter-university and multidisciplinary organization, whose several studies are the result of an experiment in Québec, having social innovation as an analytical framework for understanding such initiatives. Discussions by authors such as Lévesque, also from this cluster, approached theoretical currents of social economy and new economic sociology, discussing social innovation from the territory and social context of the actors involved [66][67][68]. Moulaert, Martinelli, Swyngedouw, MacCallum, and Gonzalez discussed social innovation from the social relations of actors, from the perspective of "bottomup" governance and training of actors involved, in addition to discussions on urban development and territorial transformation [62,69].
Finally, cluster 4-yellow, presents a theoretical discussion more related to sustainability, transition to sustainability, and transformative social innovation [33,70,71], with part of the discussions referring to the policies of transition to sustainability and social innovation, as well as networks and movements to address social challenges [72][73][74].

Country Co-Author Analysis
The analysis of co-authorship between countries allows for a demonstration of the structure of collaboration networks and partnerships in research, providing the identification of collaborations between countries and institutions. This type of analysis has part of the discussions referring to the policies of transition to sustainability and social innovation, as well as networks and movements to address social challenges [72][73][74].

Country Co-Author Analysis
The analysis of co-authorship between countries allows for a demonstration of the structure of collaboration networks and partnerships in research, providing the identification of collaborations between countries and institutions. This type of analysis has been widely used to understand and assess patterns of scientific collaboration. The map generated by the VOS shows the dispersion of the field, led mainly by six countries:

Discussion and Conclusions
This study defined and analyzed the concept of social innovation and mapped the scenario of scientific publications and the intellectual structure of the field, in the area of social sciences, management, and business. The study brings important contributions to the field mapping, considering the substantial growth of scientific publications in the area [25]. The expressive growth is reflected in the number of annual publications over the last three years (more than 1200 annual publications, in the Scopus database). The first mentions of SI appeared in the 1970s [29], however, the expressive growth of the area took place only in the last decade, representing more than 88% of the total publications. Likewise, the SI concept, initially treated as improved actions or new ways of doing things, has undergone significant improvements and advances in recent years, including in its definitions of both the satisfaction of social needs and the adoption of new social relations, which have become more inclusive and emancipatory [8,63,75]. Thus, in the theoretical context, relationships between the solution of social needs and problems and the social process through which it is developed were established.
However, although the scientific literature on SI has increased by more than 500% in the last 10 years, the field is still fragmented, lacking further studies in this direction. The relevance of the topic can be seen in the number of publications and in the journals, with the main journals with publications on social innovation: Sustainability (76 articles), Journal of Social Entrepreneurship (32), Technological Forecasting and Social Change (24), Innovation: The European (23), Social Enterprise Journal (23), European Planning Studies (21), and Voluntas (17). Furthermore, the results indicate that despite being a relatively young field of study, SI research has developed and consolidated in several study centers (e.g., Stanford University's Center for Social Innovation, INSEAD, CRISES, The Young Foundation, TEPSIE, Waterloo Institute for Social Innovation and Resilience), as well as programs funded by the European Union. In this sense, social innovation does not have fixed borders and its research is developed in a comprehensive and intersectoral way, which is why studies have been propagated in an interdisciplinary scope.
Co-citation analysis revealed that the most influential articles in the field, based on the ranking of most cited articles, were those by Boons and Ludeke-Freund (912 citations) [31] and Voorberg (717) [32], out of 1192 total articles. Other relevant documents were those by Seyfang and Hexaltine (479) [33] and Cajaiba-Santana (354) [8], respectively. Regarding the analysis of co-occurrence of keywords, the terms with the highest frequency and strength of linkage, indicating greater proximity of association with each other, were: "social innovation" (1100 occurrences, 3209 link strength), followed by "innovation " (269, 1644), "social innovations" (151, 633), "social entrepreneurship" (120, 411), and "sustainability" (8,433), reinforcing the finding that the SI literature is strongly associated with the context of innovation, social entrepreneurship, and sustainability. Among the terms with the lowest frequency of co-occurrence and weak association were "technology transfer" (5,16), "knowledge management" (5,16), risk (5, 16) "actor-network theory" (5, 13), and "scaling" (5,13). Thus, such terms with less frequency and weak association may indicate possible research gaps for future studies. Given the nature of the initiatives, studies that advance towards the transfer of technology from social innovations, understanding how the knowledge management of such initiatives takes place, as well as the networks of actors that establish themselves and scalability, can contribute to practice and to filling these gaps in the literature.
The results of this study also showed a network map organized into four main theoretical domains: (1) social entrepreneurship and the third sector; (2) strategic management and innovation; (3) sociopolitical aspects, urban development, and governance; and (4) innovation and sustainability. The first set of debates is related to aspects such as the creation of social value, motivation, and entrepreneurial orientation of the initiatives, among others [53,76]. The second set of debates is related to technological innovation, innovation systems, resources, and resources [40,[77][78][79][80].
The third set of debates involves discussions on sociopolitical aspects and urban development, and several studies in this group addressed the public sector. The main aspects that have been analyzed are the historical and social context of social actors, the socio-political and institutional capacity of actors, actor networks, social economy, and social capital [14,81]. Furthermore, discussions involving urban development and governance have emerged from these debates, including local and territorial governance, trust relationships, territory, community, local leadership, network relationships, and urban development [82][83][84][85][86]. Finally, the last set of debates is directed towards innovation and sustainability, discussions that have been growing in the field [31,58,87]. Not by chance, these terms are among the most frequently used keywords.
After interpreting the titles and abstracts of the main articles within the clusters, it was possible to reach conclusions similar to what has already been discussed. There are several studies related to the context of social entrepreneurship, adopting traditional approaches to entrepreneurship or social entrepreneurship as a theoretical perspective, as well as theoretical approaches related to strategic management, such as the theory of stakeholders, resource-based view (RBV), and corporate social responsibility (CSR). Studies have expanded the concept of CSR to the concept of territorial social responsibility (TSR), expanding the notion of responsibility of organizations and institutions for the territory to be co-responsible for the social, economic, and environmental situation of the territory in which they operate. Such theoretical discussions have advanced in relation to the management of organizations, as well as in relation to innovation and sustainability, as this co-responsibility is understood as the ability to contribute to a model of innovation, development, and social transformation in a responsible, solidary, and sustainable way [85,86]. In addition, there have been a significant amount of studies adopting innovation, sustainability, and urban socio-political development as theoretical lenses. Such findings were based on the analysis of the co-citation of the most cited authors and journals. The analysis of the co-occurrence of keywords also reinforced this finding, indicating that the most frequent topics were the ones mentioned above.
Regarding the proposed objective, the study mapped the scientific production of the SI, through the analysis of the main articles, authors, keywords, and countries, advancing the understanding of the intellectual structure of the area by identifying four major theoretical domains and possible gaps for future research.
Participation in the study was academic, associative, and political, as the interest in social innovation is due both to dissatisfaction with traditional business models and dissatisfaction with socio-environmental problems not resolved by existing government structures [75,88].

Limitations and Future Research
In this section, a future research agenda will be elaborated. However, before doing so, we must recognize an important limitation: The main selection criterion was that the article (from a magazine or book) should contain the word "social innovation" or "social innovat*" in the title or abstract. It is possible that other studies that have addressed the topic of social innovation but have not mentioned it in their title or abstract have not been included in the analysis, and relevant studies may have been neglected. Another possible limitation of the study concerns the use of a single database (SCOPUS)-although it is considered the largest database, with the main scientific journals listed, relevant studies published only in other databases may not have been considered.
For future studies, it is suggested to develop research that takes into account the terms with less frequency and weak association, namely: (1) technology transfer, (2) knowledge management, (3) risk, (4) actor-network theory, and (5) scaling. SI is the result of a network's interaction with multiple actors, involving users/citizens, third sector organizations, public and private institutions, and also policymakers [89]. Studying SI from network-based theories and seeking to understand how actors build them can help in understanding and advancing this innovation model. This can provide a basis for a discussion on the theory, measurement, and scalability of social innovation.
Other study gaps are related to knowledge management and technology transfer, which is a necessary path for the consolidation, replication, and progression of local social initiatives, in an attempt to broaden socio-technical systems [33]. Suggestions in this direction are to investigate how associations and actors learn to develop social innovations, through the generation and acquisition of tacit and explicit knowledge. Furthermore, it is possible to investigate how the generation of knowledge takes place through the socialization and sharing of collective experiences [90]. Recent studies have investigated social innovation initiatives in the context of the COVID-19 pandemic, further studies related to this context are also needed and can contribute to the advancement of the area [85,91]. In this sense, research can contribute to the systematization of knowledge and encouragement of social innovation.