GENDER DIVERSITY ON CORPORATE BOARDS: REVIEW AND FUTURE RESEARCH AGENDA THROUGH BIBLIOMETRIC MAPPING

How to this on corporate brought the total number of results to 352 articles. VOSviewer software was employed for the purpose of analyzing these articles which helped in the formulation of bibliometric citation, co-citation, and co-word maps. The findings suggest the prominent countries, significant authors, major studies, and top journals in this domain. In addition, the study also identifies the various dimensions such as financial performance, social performance, environmental performance, sustainability disclosures being impacted due to the presence of gender diversity. The study is significant and unique based on the pretext that it uses the Scopus database for the purpose of bibliometric mapping whereas past studies have used the Web of Science database, thus the study’s outcome made a strong corroboration in identifying emerging paradigms in the gender diversity literature.

for the slow-paced growth of women can be attributed to various reasons which are collectively known as the "glass ceiling" (Heredia, Ramos, Sarrió, & Candela, 2002). These obstacles, based on the societal perceptions, can take several forms including favoritism of male directors for other male directors (Hutchinson, Mack, & Plastow, 2015), the tendency of directors to feel more comfortable among directors from the same gender and demographic as per the similarity attraction theory (Chatman & O'Reilly, 2004), and the idea of prestigious occupations such as directorship belonging to males (Ridgeway, 2014).
The challenges amidst the growth of women directors on corporate boards are not just restricted to male directors but also certain perceptual biases of female directors, for example, due to the occupational identity threat females feel that growth in the number of females will lead to a fall in the esteem they have in the occupation (Cacouault-Bitaud, 2008), and, therefore, Queen Bee strategy is adopted by females to distance themselves with the other females (Derks, Ellemers, van Laar, & de Groot, 2011). The advancement of women studies has given rise to various phenomena that portray various kinds of reasons that showcase the situations due to which even if women are being employed on board, they are not able to escalate to the upper echelons. One such phenomenon is the "double burden syndrome" that highlights the dual responsibilities of household along with the professional responsibilities of work which are considered as traditional gender-based responsibilities (Hochschild, 1990) this does not permit the women directors to take up higher responsibilities even if they wish to owe to lack of efficiency (Bratberg, Dahl, & Risa, 2002).
Another theory that documents the low representation of women on corporate boards is the concept of "glass cliff" that emphasizes the appointment on women on boards only in the situation of crisis when the firms are struggling to perform and there is a high likelihood of failure (Francoeur, Labelle, & Sinclair-Desgagné, 2008;Ryan & Haslam, 2007). Moreover, in case the situation of these firms deteriorate post appointment of women on boards, which in any case has been done noticing crisis, they shall be soon replaced by their male counterparts (Cook & Glass, 2014). Another deterrent theory is the concept of the sticky floor which is a slight contrast to the glass cliff theory and states that women are equally appointed as often as males, but they tend to receive lesser compensation (Adams & Funk, 2012). In addition to the above phenomena, women have also addressed semihostile work environments with regard to stereotyping, gender discrimination, and social exclusion (Abdalla, 2015).
The act of promoting adequate gender representation on corporate boards is not merely a social phenomenon to promote gender equality, but rather the presence of diversity can accord various economic benefits to the firms. The same can be justified with the help of agency theory, upper echelon theory, stakeholder's theory, as well as resource dependence theory. Agency theory postulates that the presence of women directors shall reduce the information symmetry and hence improve the CSR quality and thus will also lead to the reduction in the agency issues (Reguera-Alvarado, de Fuentes, & Laffarga, 2017). Stakeholder theory supports women's presence by suggesting that women possess more communal qualities than men, such as helpfulness, kindness, sympathy, interpersonal sensitivity, etc., which may facilitate their say based on stakeholders' claims and expectations (Eagly, Johannesen-Schmidt, & van Engen, 2003). In contrast, upper echelons theory (UET) suggests that the prior experiences, value systems, and knowledge of the directors impact their decision-making, and men and women, therefore, bring different sets of strategies into the boardroom (Byron & Post, 2016). Resource dependency theory also advocates that the female directors' presence shall turn out to be fruitful for the CSR disclosures since they would through their connections entail legitimacy between the society and stakeholders (Lückerath-Rovers, 2013). In this sense, gender diversity on boards helps in better decision-making, since women are more inclined towards asking questions and they make sure that the decisions are not finalized without adequate discussions (Konrad, Kramer, & Erkut, 2008).
The objective of this bibliometric review was to identify the theoretical and intellectual evolution in the domain of gender diversity on corporate boards. We believe that the concept of gender diversity on corporate boards affects the decision-making and, in turn, would impact the practices undertaken by the firms. This paper throws light on the following research questions: To answer these research questions, we systematically explored the various studies conducted on the theme of gender diversity on corporate boards using the Scopus database. The study is also unique in the sense that past studies have focused on the Web of Science database (Sánchez-Teba, Benítez-Márquez, & Porras-Alcalá, 2021) thus, the study would be helpful in identifying and complementing various emerging paradigms in gender diversity literature. The keywords that were used for finding the research articles were: women on board and board gender diversity. Further, bibliometric analysis was used to identify the various dimensions in which the studies have been conducted and what are the emerging domains of research in this area. VOSviewer software was used as a tool that helped us create the mapping based on the bibliometric citations, co-citations, and word maps. This further enabled us to identify and evaluate the major thrust areas where research has been conducted, the dominant journals extensively publishing, major countries in which research has been conducted, etc.
The remainder of the paper is organized as follows. The second section comprises the literature review that describes the various studies conducted in this area in a chronological pattern. The following section deals with the methodology used for the collection of the research studies, literature review, and sample. The fourth section comprises the analysis of the bibliometric maps. The last section deals with the results and conclusions.

LITERATURE REVIEW
The theme of board gender diversity impacting firm performance has been the center of focus for researchers across the globe. According to Torchia, Calabrò, and Huse (2011), women can add unique perspectives, experience, working styles, more wisdom, good atmosphere in the boardroom, they are also found to have different values and are more sensitive to women issues. There are multiple theories, such as agency theory, resource dependence theory, upper echelon theory, etc., that clearly project the needs of creating a gender-diverse board. These theories have become the basis for academicians, policymakers, as well as regulators for formulating the legal regulations which shall put a thrust on such issues (Moreno-Gómez, Lafuente, & Vaillant, 2018 (Mukarram, Ajmal, & Saeed, 2018), the moderating role of industry-based sensitivity (Qureshi, Kirkerud, Theresa, & Ahsan, 2020) have also been studied to some extent.
Despite growth and advancement, there are various aspects of board gender diversity where the literature is still in the state of dilemma, and the research in this area needs further exploration and investigation. Through this study, various research avenues shall be identified, research gaps shall be bridged and future directions for research shall also be established.

RESEARCH METHODOLOGY
The study focuses on the bibliometric analysis of the research articles on the topic of gender diversity on board based on the data (research articles) retrieved from the Scopus database (www.scopus.com). Though the Web of Science database is often considered a more popular database, the Scopus database launched by Elsevier in 2004 is found to have a broader database in social sciences, significantly covering more than 16 million references dating back to 1996 (Vieira & Gomes, 2009). Since the area of gender diversity is deeply rooted in the discipline of corporate governance, which saw an upsurge in the late 1990s, the Scopus index database by Elsevier was found to be the best match for the same. The above argument was further corroborated by various scholars as well (Mongeon & Paul-Hus, 2016). Based on the preliminary search of keywords: gender diversity and women on boards, a total stream of 547 articles were found. Accordingly, in the second phase filters were places to screen out those articles which were not connected to the subject of the study, and we have only considered full articles, and have excluded publications, such as book chapters, conference papers, editorials, etc., since they ideally do not go through a full-fledged review process. After adequate refinement and filters in the second phase, a total of 352 articles were found relevant for the study which were published during the years 1983-2021. In the final phase, abstracts of 352 articles were scrutinized to eliminate those which did not belong to the subject domain.

ANALYSIS RESULTS
Firstly, based on the data extracted from the Scopus database, the author employed various descriptive statistics for the generation of various tables and graphs that could help in the identification of patterns within the database. The trends were identified in terms of the number of publications, top publishing countries, journals, top authors, most cited articles as well as the evolution of the keywords.
The author made use of citation, as well as co-citation analysis, to identify the features of the area of gender diversity on corporate boards to enhance the intellectual base (Zupic & Čater, 2015). Citation analysis refers to the frequency with which a research article or a document is cited or used by other papers located in the same database (Scopus, in this case). The author made use of the citation analysis to evaluate the top countries, journals, influential articles in the domain of gender diversity based on the number of citations (Tables 2-4).
Co-citation analysis helps us supplement the citation analysis by enhancing the intellectual base in a particular area by examining two research articles or documents which have been cited in a common document (Small, 1973).
The findings of the bibliometric analysis have been laid down in the order of research questions based on the gender diversity on the board domain.

Volume and trend analysis of published studies
The primary analysis is based on the volume of publication in the gender diversity domain. The final number of research articles post-filtration was 352 over a period of approximately 32 years (1989-2021) which represents that the area of gender diversity has not seen extensive publications but is growing at a rapid pace. Also, Table 1 points to the fact that Norway was the first country which passed mandatory legislations of gender-based quota in the year 2003. This further led to the series of legislations being passed in other countries leading to the gender diversity domain receiving wide scholarly attention.
Trends and evolution in the area were analyzed based on seeing the annual growth in the volume of publications. Figure

Publication by countries
The number of articles considered for the study was spread across 74 countries throughout the world. This clearly points to the fact that the gender diversity area has received wide attention globally and is not limited to certain continents. Table 2 provides the list of the top 20 most active countries with at least five publications in gender diversity on board. The US tops the list with 64 research publications and three thousand six hundred and thirty-six (3636) citations followed by the UK with 52 publications and nineteen hundred and sixtyfour (1964) citations. The third spot is captured by Australia with 34 documents and sixteen hundred and eighty-one (1681) publications. Gender diversity on board is majorly connected to the corporate governance literature and the UK being the pioneer based on its Cadbury Report (The Committee on the Financial Aspects of Corporate Governance, 1992) and the US and Australia being the countries which have seen major corporate scams during 2000, the results are not surprising at all. The area would have received greater attention with a view to leverage out gender diversity-based advantages.  Table 2 also highlights an important aspect that more than 70% of the research on gender diversity has been conducted in the developed economies especially from Europe. The plausible reason that could explain such phenomenon is the emergence of OECD which has taken a strong take on corporate governance issues. Figure 3 provides a visual representation of the relationship between the various countries, through a bibliometric citation map.
Though the number of publications in emerging and developing economies is not much, we could still notice a sound number of publications of the countries like India and Pakistan which could be to test the impact of gender diversity post their mandatory provisions.

Publication by journals
Next, we focus on describing the top journals publishing in gender diversity on board. The articles that were considered for the bibliometric analysis were spread across 155 journals throughout the world under several domains, such as ethics, corporate governance, finance, gender, accounting, economics, strategic management, psychology, etc. which also confirms that the gender diversity area has found its place in some of the top journals and the area has wide scope for further exploration. Table 4  Accounting, etc., that portray the multidimensional aspect of the gender diversity issue.
A quick glance making a comparison between Table 3 and Table 4 Figure 3 represents the journal co-citation analysis (JCA) that complements the outcomes of the citation analysis represented in Table 4. The various-sized bubbles or the nodes depicted on the JCA map represent the number of co-citations associated with the respective journals. The journals which are located closely are co-cited frequently (Zupic & Čater, 2015) or have been cited in similar content-based articles. The links associated with these nodes or bubbles act as an indication of the co-citation of articles that appear in these related journals. The frequency of co-citation of these research articles with related journals helps in the determination of the color of the nodes. Thus, common color nodes of these journals depict association or similarity in the contents being published (Zheng & Kouwenberg, 2019).
The JCA represents 4 major distinct sets of clusters that are associated with journals represented with unique areas or subject-based dimensions. The red-colored cluster is associated with Finance and Economics, the green color represents a majority of Management and Strategybased journals, the blue color focuses on Accountingbased journals, and, finally, the yellow color comprises miscellaneous journals from the area of Governance, and Business Ethics. The focal point of the JCA map comprises of Journal of Business Ethics and Corporate Governance: An International Review which is associated with all the disciplines (Finance and Economics, Management, Strategy, and Accounting, as well as Governance and Business Ethics). Moreover, the Academy of Management Journal, as well as Journal of Financial Economics, are the most impactful journals in the discipline of Management, Finance, and Economics. Figure 3 substantiates the outcomes derived based on the citation analysis represented in Table 4 which highlighted the presence of gender diversitybased articles in multi-discipline areas-based journals, such as Finance, Economics, Management, Strategy, and Accounting apart from Governance and Ethics.
Finally, based on the dual dimension of co-citations impact (number of co-citations), as well as boundary-based extension (links to the other journals), Journal of Business Ethics and Corporate Governance: An International Review is found to be the most impactful, as well as influential, journals publishing in gender diversity.

Influential articles
The bibliometric analysis also helps us identify those research articles available in our database which have made a significant impact in the area, or the discipline being studied. Citation analysis helps in measuring the number of times a particular research article has been quoted or cited after being used by the other documents. It also helps to determine the impact of the article on the scientific community (Ding & Cronin, 2011). Table 5 lists down the top 20 most cited papers based on the citations available in the Scopus database. The list provided in Table 5 re-confirms the impact and dominant position of the Journal of Business Ethics as 8 out of 20 (40%) of the top 20 most influential articles are published in this journal. Campbell and Mínguez-Vera (2008) were among the pioneer authors to study the impact caused by gender diversity on boards on firms' financial performance. They found in their study that gender diversity on board based on parameters such as percentage of women on board, diversity indices like Blau and Shannon have a positive impact on firms' financial performance whereas the reverse relationship is not true. Bear, Rahman, and Post (2010) extended the knowledge base of gender-based literature by evaluating the relationship between board diversity and gender aspect on corporate social responsibility and firm reputation. The study found positive linkages between gender diversity and firm reputation mediated through the CSR ratings. Miller and del Carmen Triana (2009) brought an interesting dimension through their study, where they found that board racial and gender diversity are not causally linked to the firm performance rather, they are partially mediated by firm reputation and innovation. They also found positive linkages between gender diversity and innovation.
We came across an interesting aspect represented by Table 5, that 12 out of 20 most cited articles (60%) were focused upon linking gender diversity and financial performance aspects in various forms. Now, to enhance the intellectual base of the literature we performed the document co-citation analysis (DCA). DCA is performed to extend the literature to a wider number of research articles, where 21630 referenced articles were considered for the analysis. The top 20 most co-cited articles are represented in Table 6.
The list of articles in Table 6 demonstrates that "Women in the Boardroom and their Impact on Governance and Performance" (Adams & Ferreira, 2009) is the most cited and impactful article in the gender diversity literature. The study found that gender-diverse boards trigger the board-related aspects in terms of governance, and this leads to an impact on a firm's financial performance. Though the paper was not part of our Scopus database but has received the highest co-citation owing to its impactful literary contribution. They also concluded that mandatory women quotas are detrimental to a firm's performance. Table 6 Table 6 clearly depicts and confirms the premier position held by the Journal of Business Ethics and Corporate Governance: An International Review as both these journals account for 25% (5 each) out of the 20 most co-cited articles.  To respond to the final research question, we made use of the keywords occurrence analysis that helped them identify the most widely studied topics as well as their association with other dimensions.
In the words of Zupic and Čater (2015), "When words frequently co-occur in documents, it means that the concepts behind those words are closely related. The output of the co-word analysis is a network of themes and their relations that represent the conceptual space of a field" (p. 435). The co-occurrence of these keywords acts as an important tool to identify the trends as well as various dimensions of scientific research in a particular area (Madani & Weber, 2016) which have been studied by academicians and scholars.
The keyword co-occurrences were conducted based on the "all keywords" and it led to the identification of 45 keywords with a minimum of 5 occurrences. The keywords that dominated the co-occurrence analysis were "Corporate Governance" (112 cases), "Gender Diversity" (100 cases), "Board of Directors" (54 cases), "Corporate Social Responsibility" (25 cases), and "Firm Performance" (23 cases). The results clearly re-affirm the dominant linkage of gender diversity with corporate governance mechanisms as has been found in the "canonical" paper of Adams and Ferreira (2009). The other major dimensions that have been widely explored were the implications on corporate social responsibility and firm performances.
Another added feature of conducting a co-occurrence keyword analysis is to identify the "emerging research topics" which shall provide directions for future research in the same discipline as well as associated disciplines. Through the VOSviewer software author has also constructed a visualization keyword co-occurrence map of the literature keeping the threshold occurrence level as 5. The rationale behind keeping a low occurrence count is, the gender diversity literature is an emerging topic and does not comprise many frequently occurring keywords.
To have a comprehensive idea of the emerging topics the author has eliminated some of the keywords such as gender diversity (100 cases), as well as some other related terms, such as women on boards (35 cases), etc., due to their extreme and frequent occurrences.
The keyword occurrence map primarily focuses on two aspects: firstly, the frequency of occurrence of keywords and, secondly, the transition in popularity of these keywords over a period. Figure 4 shows a depiction of the most frequently used keywords over some of the past decades.
The emerging research topics can be identified from Figure 4 based on the light green as well as yellow colors. On the parameters of frequency as well as recency the topics that have emerged significantly in the last few years are Sustainable Development (7 cases), Environmental Performance (7 cases), Innovation (7 cases), Agency Theory (6 cases), Board Size (5 cases) and Corporate Social Responsibility (CSR) Reporting (5 cases). These are some of the emerging topics that can be built upon by scholars and academicians for future research.
The emerging studies have focused upon the role of gender diversity on sustainable development (Bravo & Reguera-Alvarado, 2019; Sumedrea, 2016; Valls Martínez, Cruz Rambaud, & Parra Oller, 2019) and they have also found that bringing together of the diverse range of expertise and knowledge in the form of women's representation on board would improve decision making in the context of sustainability (Nadeem et al., 2017). Furthermore, it has also been found that women directors tend to show a greater inclination towards the community service projects as compared to the male directors (Groysberg & Bell, 2013) and they are found less guilty of violations related to environmental concerns (Donaldson & Preston, 1995), this has further led to policy thinkers invoke more stringent gender diverse laws and policies.
Another topic that has received attention in the gender diversity literature in recent years is how do gender diversity impact environmental performance ( ). The typology of female directors, such as independent and outside directors, is also a growing stream that impacts CSR disclosures (Cabeza-García, Fernández-Gago, & Nieto, 2018). We also notice the prevalence of the terms like "agency theory and "innovation" in the knowledge base of gender diversity literature, therefore, future studies can also be linked to measuring the moderating role of agency theory or innovation and gender diversity on various dimensions, such as sustainability, environmental performance, and CSR reporting.

CONCLUSION
The bibliometric analysis clearly reveals that the knowledge base of gender diversity on boards has grown exponentially from 1989 to 2021. The study reveals that the literature has diversified globally and is spread across 74 countries but there is a dominance of studies conducted by the developed nations like the US, the UK, Australia, Spain, France, Germany, etc. The plausible reason for the same could be the inherent linkage of the gender diversity literature with corporate governance, and since these developed nations were the pioneers of various corporate governance codes, the outcome seems justified. There also appears to be growing in the research studies conducted in the developing economies post-adoption of mandatory and voluntary codes for women directors' appointments.
The citation, as well as co-citation analysis, reveals the multidisciplinary nature of the topic covering journals across various subjects, such as Finance, Economics, Management, Strategy, Accounting, as well as Corporate Governance, and Ethics. The two most influential journals that should be of most interest to scholars working in the gender diversity area are Journal of Business Ethics and Corporate Governance: An International Review. Though considering the multidisciplinary nature, Journal of Financial Economics and Academy of Management Review, are also well sought-after journals that could be of insight. These journals portray potential publishing avenues for scholars and researchers.
Moreover, the inherent linkage of the Gender Diversity area towards Corporate Governance impacts several other dimensions through the decision-making attribute of the board, such as Finance, Corporate Social Responsibility, Sustainability, Leadership, Accounting, etc. Another valuable contribution made with the help of citation analysis is to identify the pioneer articles that have made a significant impact on the intellectual development of the area. The two pioneer studies by Campbell and Mínguez-Vera (2008) and Bear et al.
(2010) threw light on two major dimensions of gender diverse boards that is Financial Performance and Corporate Social Responsibility, respectively. These studies were the steppingstones for other scholars to explore the dimension of gender diversity in both developed and developing economies.
The distribution of literature in the various multidisciplinary subjects along with the keyword co-occurrence analysis affirms wide scope of research in developing economies as well as several dimensions that have seen meagre growth and development. Since developing economies widely differ from developed ones owing to weak legal frameworks (Djankov, La Porta, Lopez-de-Silanes, & Shleifer, 2008; La Porta, Lopez-de-Silanes, Shleifer, & Vishny, 1997) along with the prevalence of concentrated ownerships (Claessens, Djankov, & Lang, 2000). The keyword evolution map highlighted various emerging topics in the literature that can provide a future scope of the study for the researchers; some of the prominent ones being Sustainable Development, CSR Reporting, Environmental Performance as well as Innovation. We would like to suggest that though some past contributions Despite the great contribution of this study, the study also has its share of innate limitations like various other studies. The primary limitation of this study is that a single database (Scopus) has been used for the collection of the research studies. This could have led to the missing of various other studies that could have been collected from multiple data sources. This shall also limit the interpretation of the results to some extent.
The study has certain practical, as well as managerial, implications as the study throws to light various elements where the benefit of gender diversity could accrue and can help the firms in better decision-making. For various firms, it also opens policy implications where they could understand the relevance of having adequate gender diverse representation on the board. The literature clearly points towards the critical mass aspect of gender diversity (Lafuente & Vaillant, 2019; Yarram & Adapa, 2021) and the benefits that might accrue from the same. The literature clearly points towards other interdisciplinary aspects, such as corporate sustainability, innovation, CSR reporting, agency theory, etc. Policymakers, as well as scholars, must identify these research gaps and dimensions and must address these gaps in future studies.