{'fraction_non_alphanumeric': 0.04268423883808499, 'fraction_numerical': 0.02560516406670253, 'mean_word_length': 5.078306359326467, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 6, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Cause-related marketing: a systematic review of the literature

Cause-Related Marketing (CRM) is one of the most versatile activities among the Corporate Social Responsibility (CSR) initiatives. Though CRM is extensively researched, however, only a few authors have performed systematic literature reviews on CRM. Therefore, more systematic reviews of CRM are still needed to complete and bring together the more contributions, advances, and different existing research lines. Thus, this paper provides a comprehensive overview of the existing literature in CRM from the two keywords: “Cause-Related Marketing” and “Cause Marketing”, and the time period ranges from 1988 to 2020. In this study, rigorous protocol is used in synthesizing 344 English articles drawing upon e-journal database searches. These articles were categorized by time-wise development, country-wise development, methodological development, cross-cultural analysis, the role of journals. This study also carried out the Bibliometric Analyses. The review highlights that the concept of CRM has evolved from being considered a marketing mix tool (a promotion tool), to being considered as a CSR initiative, with a more strategic character. Our findings revealed that only a few journals published articles on CRM. Geographically, the CRM study was initiated in North America, followed by Europe and Oceania, and Asian and Sub-Saharan African countries. From the third decade, there was more collaboration in cross-cultural studies and the use of mixed-method (qualitative and quantitative studies) approach. Lastly, this study shows the most manifest research gaps in CRM that opens avenue for future research.


Introduction
Cause-Related Marketing (CRM) is a versatile and growing activity in the marketing field. It provides opportunities to profit and non-profit organizations, and consumers, to participate in a social cause (Varadarajan & Menon, 1988). Since 1988, CRM initiatives have gradually increased for more than three decades. CRM allows to achieve the societal and financial corporate establishment's goals, as well as provide the opportunity to consumers to participate in an altruistic act.
Formally, the first CRM campaign named in this way was carried out by American Express (AMEX) in 1983, in the United States. The purpose of this program was to increase the usage of the AMEX credit card, but also collect money to be donated for the renovation of the Statue of Liberty. This project was developed from September to December, and the donation was $1.7 million (Varadarajan & Menon, 1988). Since then, and according to the IEG Sponsorship Report, cause sponsorship spending in North America has grown continuously 1 from $120 million in 1990 until $2.23 billion in 2019. In 2020, due to the COVID-19 pandemic, U.S. sponsorship value was $10 Billion (annually), which approximately increased 38% (IEG, 2020), as shown in Fig. 1.
Consequently, the practice of CRM has also increased for the last three decades because more profit organizations have engaged in CRM activities (Adomaviciute et al., 2016), non-profit organizations have maintained environmental protection, health, and other worthy causes (Grolleau et al., 2016), and when consumers purchase the CRM products for support the cause, they have a prosocial behavior (Chang & Chu, 2020) and feel happy (Jeong & Kim, 2020;Vrontis et al., 2020).
During this time, CRM has become a topic of considerable debate in both managerial and academic circles worldwide. Although some systematic literature has been presented on this topic (see, for example, Guerreiro et al., 2016;Lafferty et al., 2016;Natarajan et al., 2016;or Thomas et al., 2020), an updated systematic literature review is required. Thus, we present a new systematic literature review: (1) To complete the review of the academic research articles in the area of CRM, from 1988 to 2020, with the perspective of profit organizations, non-profit organizations, and consumers over the last three decades; (2) To include cross-cultural studies; (3) To include studies carried out in developed and developing countries; (4) To include studies executed in different societies (e.g. Muslim societies, Western societies with Christian traditions, etc.); and (5) To conduct a bibliometric analysis using VOSViewer Software.
Thus, the main objective of this paper is to provide a systematic literature review of the existing research in the field of Cause-Related Marketing. More specifically, our aim is to find influential papers that have shaped this field and provide the overview of historical development in the field of research, focusing first on previously analyzed criteria: Time-Wise Development of CRM Literature, Country-Wise Development of CRM Literature, Methodological development in CRM Literature, and Role of Journal in Development of CRM literature. But also, this study carries out a systematic review with a bibliometric analysis. On the one hand, the systematic review helps the researchers to improve the rigor of prior reviewing literature. On the other hand, bibliometric analysis helps to analyze divergent views and examine the development of the CRM field.
Hence, this paper has followed two steps in the systematic literature review on CRM: (1) to select the inclusion and exclusion criteria, and (2) to analyze the evolution of CRM in seven different categories.
First step: Inclusion and Exclusion Criteria.
-This research only included published papers in journals, from 1988 to 2020 (data sources such as working papers, reports, newspapers, textbooks, conference papers, or theses / dissertations, were not included). -Two keywords, "Cause-Related Marketing" and "Cause Marketing", were used to search the databases (SAGE Publications, JSTOR, Emerald Full Text, Springer, John Wiley Publications, Elsevier, Taylor and Francis, and Google Scholar). -This research also used conceptual review and empirical studies of different countries. -This research only included papers written in English (i.e., non-English language research articles were excluded). -This study considered the date of publication of the journal as the date of the research articles.
Second step: Academic researchers have used qualitative and quantitative methods for literature review to organize and provide the above underlying findings on CRM. And according to Liu et al., (2015), Bibliometric Analysis is a tool to examine literature review. Thus, this study has also provided a static and systematic picture of the research (Aria & Cuccurullo, 2017). This study relies on bibliometric techniques such as author-citation analysis, or co-words or co-occurrence analysis, and   Poje & Groff (2021). We also considered adding a new category that had not been considered in previous studies: cross-cultural analysis. Therefore, the structure of this paper is organized as follow: firstly, we show the CRM theoretical background (with a previous introduction to CSR, to link it with CRM, because CRM is generally considered under the umbrella of CSR -e.g., Kotler and Lee, 2005;Galan-Ladero, 2012); secondly, we offer the results of our literature analysis in the CRM field; later, we discuss these results; and finally, we offer the main conclusions, also considering the main limitations of this study and further research.

Background
Since the inauguration of the third millennium, Corporate Social Responsibility (CSR) has become a globally hot issue by the rapid change of the environment. A large number of organizations, from developed and developing countries, have focused on CSR.
CSR, defined as "a concept whereby companies integrate social and environmental concerns in their business operations and in their interaction with their stakeholders on a voluntary basis" (European Commission, 2001), has a wide range of history: it started in Western countries, but later, it spread all over the world. Antecedents of CSR can be found at 18th and 19th Centuries, with the creation of welfare schemes adopted with a paternalistic approach, to protect companies and retain employees with improved life quality (Carroll 2008). But it is in the twentieth Century, and specifically after World War II, when scholars and practitioners discussed about the social responsibilities, and successful businesses also adopted such responsibilities (Heald, 1970).
Thus, CSR started to be established and, in the last seven decades, it has played different roles: -The 1950s was the first era that established the current CSR. Successful business leaders and board of directors moved towards the ethics of society. Bowen, the first who coined the term, introduced the concept, and provided the initial definition of CSR, described as "the obligations of businessmen to pursue those policies, to make those decisions, or to follow those lines of action which are desirable the objectives and values of our society" (Bowen, 1953, p. 6). In this area, Heald (1957), discussed that businesses do not only serve on economic performance work, but they also serve on humane and constructive social policies.
-The 1960s : Many of the definitions of CSR are formalized. Walton (1967) was a prime thinker who addresses the different aspects of CSR: "In short, the new concept of social responsibility recognizes the intimacy of the relationships between the corporation and society and realizes that such relationships must be kept in mind by top managers as the corporation and the related groups pursue their respective goals (Walton, 1967, p. 18)".
-The 1970s : Friedman described that the social responsibility of business is to enhance profits and maximize shareholder value. Therefore, Carroll (1979) came in this decade with the new concept of CSR, defined as "the social responsibility of business encompasses the economic, legal, ethical, and discretionary expectations that society has of organizations at a given point in time".
-The 1980s : the notions of stakeholder management and business ethics had become the main integral part of the business (Carroll, 2008). In 1980, Jones proposed that CSR is a process, not the outcome, and CSR, when engaged in as a process of decision making, should constitute CSR behavior by the corporation (Jones, 1980). Also, Aupperle et al. (1983) suggested that four aspects include CSR: economic, legal, ethical, and voluntary or philanthropic responsibilities.
-The 1990s : Carroll (1991) revised the concept of CSR and introduced the "Pyramid of Corporate Social Responsibility". He described four main responsibilities of the company: economic responsibility ("be profitable"), legal responsibility ("obey the laws and regulations"), ethical responsibility ("do what is just and fair"), and philanthropic responsibility ("be a corporate citizen"). During this decade, Elkington (2001) introduced another concept of CSR, the "Triple Bottom Line", which focuses on three issues: social responsibility ("people"), environmental responsibility ("planet"), and economic responsibility ("profit").
-The 2000s: CSR extends to emerging markets. After the collapse of Enron, 2 many organizations and corporations focused on establishing CSR departments, hiring CSR consultants and CSR managers. On the other hand, in 2002, ISO Committee on Consumer Policy play an important role in ISO 26000, an international standard that present a guideline on Corporate Social Responsibility. 3 -The 2010s : Kramer and Porter (2011) introduced the concept of "creating shared value", which becomes the core objective of business strategies. 2015 is an important year because the "2030 Agenda for Sustainable Development", with the "Sustainable Development Goals" (SDGs), was launched. SDGs covered a wide range of global areas, such as fighting against climate change, removing poverty and hunger, as well as promoting sustainable consumption, among others. Therefore, different theories have been created and adapted during all this time. The most important theories are Carroll's CSR Pyramid Theory, 4 Triple Bottom Line Theory, 5 Stakeholder Theory, 6 and Corporate Citizenship Theory. 7 On the other hand, CSR initiatives, formed as a part of the core business activities, provide long-term financial security and growth for stakeholders but also increase the market position (Bhattacharyya et al., 2008). Under the big umbrella of CSR, different initiatives have appeared, and they have become growing popular among profit organizations worldwide. Kotler et al. (2012) explained six different types of CSR initiatives (see Table 1), which included cause promotion, causerelated marketing, corporate social marketing, corporate philanthropy, community volunteering, and socially responsible business practices.
According to Thomas et al. (2011), CSR has received significant attention in both academic and business societies. CRM, as one of these initiatives, has progressed in social responsibility and allows firms to link their philanthropic activities and strategic marketing goals. On the other hand, CRM activities also have been an increasing part of the corporate marketing plans (Gupta & Pirsch, 2006a). Therefore, this study especially focuses on this CSR initiative: Cause-Related Marketing (CRM).
The first definition of Cause-Related Marketing (CRM) was introduced by Varadarajan and Menon (1988, p. 60), as "the process of formulating and implementing marketing activities that are characterized by an offer from the firm to contribute a specified amount to a designated cause when consumers engage in revenue-providing exchanges that satisfy organizational and individual objectives". This definition provides two main streams: to support the charitable cause and to satisfy organizational and individual objectives.
On the other hand, the most essential and significant benefit of the CRM is shown as a win-win-win situation (for the profit organizations, non-profit organizations, and consumers - Adkins, 1999). CRM campaigns increase the number of sales for the organization, as well as enhance the number of donations to the non-profit organizations (Deb & Amawate, 2019). CRM campaigns also give the best chance to profit organizations to attract the customers towards organization and enhance customer loyalty (Galan-Ladero et al., 2013b), as well as they create or enhance emotional engagement with target customers, build a strong relationship with them (Cone et al., 2003;Docherty & Hibbert, 2003), and also maintain the company's goodwill (Chang & Chu, 2020). Consequently: -The for-profit organizations use CRM as a strategic tool to build a strong brand image in the customer's mind (Ahluwalia & Bedi, 2015). And the internal benefit of the for-profit organization is to help increase the employee's self-esteem, commitment, and loyalty (Cone et al., 2003;Polonsky & Wood, 2001).  (Nowak and Clarke, 2003). On the other hand, CRM in non-profit organizations increases the number of donors (Docherty & Hibbert, 2003;Polonsky & Wood, 2001).
-For consumers, charitable causes, linked to their purchases, boost their feeling of happiness and inner satisfaction (Chaabane & Parguel, 2016), and they also feel good when helping others (Imas, 2014)

Analysis and Main results
Due to an increasing number of CRM research papers that identify the most essential and main contributions in the field, and to objectify the outcomes, then bibliometric analysis is introduced. Zupic and Čater (2015) explained the five main bibliographic methods, which consists of citation analysis, co-citation analysis, bibliographic coupling, co-author analysis and co-word analysis. In this study, we apply Co-words or Co-occurrence analysis, Co-citation analysis, and cited journals analysis. These analyses were run on VOS-software.

Analysis of the different definitions of CRM
A wide variety of definitions of CRM have been contributed since 1988 (see Appendix 1, Table 7). In Table 2, we summarize the main CRM definitions, from 1988 to 2020, according to the main keywords included in them: CRM as an activity (a marketing activity and/or a CSR activity), as a strategy, as a marketing mix tool, and as an alliance (between profit and nonprofit organizations). Thus, we can observe that there is not a general, unanimous agreement about its definition yet. However, the concept of CRM has evolved from being considered a short-term marketing mix tool (a promotion tool), to being considered a CSR initiative, with a more strategic character.

Time-wise development of CRM literature
However, in this study, we start from the time-wise development of Cause-Related Marketing. First, we identify the number of research articles into three time periods (decades) : 1988-2000, 2001-2010, and 2011-2020 (previous systematic literature did not classify them into decades). With the growing body of Cause-Related Marketing, it is better to organize it in three decades because differences are appreciated, depending on the time. Varadarajan and Menon introduced the CRM term in academia in 1988, and the following three decades witnessed gradual growth in CRM literature. Table 3 shows the annual evolution of this figure from 1988 to 2020.

Keywords Authors
CRM is an activity Varadarajan and Menon (1988) Hawkens and Stead (1996) Mullen (1997) Adkins (2007) Pringle and Thompson (1999) Hajjat (2003) Kotler and Lee (2005 In summary, we can indicate that CRM publications have grown significantly over the three decades analyzed, because more and more research papers have been published on this topic.
In this analysis, the most cited authors (and their corresponding works) for each decade have been the following: -From the first decade, the most cited authors are: Varadarajan (1988), with 734 citations; followed by Webb (1998), with 498;Smith (1991), with 121; File (1998), with 110;and Ross (1992), with 15 citations. -In the second decade, Barone (2007) is the most quoted, with 243 citations; followed by Gupta (2006a), with 189; Lafferty (2005), with 187; Cui (2003), with 152; and Berglind (2005), with 103 citations. In summary, we can highlight that Varadarajan (1988) is the most cited author of all time, with the first academic paper published on CRM, and serves as a reference for researchers around the world. And by far the next most cited authors are Webb (1998) and Barone (2007).

Co-words or co-occurrence analysis
A co-word analysis may be described as "a content analysis technique that uses patterns of co-occurrence of pairs of items… in a corpus of texts to identify the relationships between ideas within the subject areas" (He, 1999, p. 134). Thus, co-words or cooccurrence analysis is a content analysis that connects words in the title of the research paper or abstract. The main idea of the co-word analysis is to connect any identified patterns into a map of contextual space. We also applied this analysis to each decade.

First phase (period 1988-2000)
For the 13 articles published from 1988 to 2000, the co-word analysis identifies four clusters consisting of the following words (with the minimum number of occurrences of keywords defined as 1; out of 26 keywords in this period, 26 met the threshold).

Second phase (period 2001-2010)
Based on the selection of 74 articles for the period 2001-2010, the co-word analysis shows a more precise picture than it does in the introductory decade (to narrow down the result, the minimum number of the occurrence of keywords was defined as 2; out of 160 keywords, and 27 meet the reduction criteria).
-A notable cluster derived by the co-word analysis (Fig. 3, red color) consists of the words brand alliances, cause-related marketing, corporate philanthropy, corporate social responsibility, donations, reputation, social responsibility, sponsorship, and work. -A second cluster (Fig. 3, green color) comprises brand, company, consumer, framework, impact, information, price, responses, and skepticism. -The third cluster (Fig. 3, blue color) is related to advertising, brand, cause marketing, consumer behavior, marketing, and purchase intention. -The fourth cluster (Fig. 3, yellow color) consists of choice, corporate image, and purchase intention.
In summary, the co-word analysis shows that, from 2001 to 2010, the Cause-Related Marketing keyword related to the other striking keywords, such as corporate social responsibility, reputation, corporate image, and purchase intention.

Third phase (period 2011-2020)
Based on the selection of 257 articles for the period 2011-2020, the co-word analysis shows a more precise picture than it does in the previous two decades. To narrow down the result, the minimum number of the occurrence of keywords was defined as 5 (out of 825 keywords, and 40 meet the reduction criteria). The most notable clusters derived from the co-word analysis are: -First cluster (Fig. 4 In summary, the co-word analysis shows that, also for the period from 2011 to 2020, the most focused keyword is Cause-Related Marketing. Other significant keywords are ethics, purchase intention, consumer behavior, and attitudes. Consequently, the whole co-word analysis shows that all around the world, the researchers are focused on the one keyword that is "Cause-Related Marketing", and the other most emphasis keywords are philanthropy and consumer perception, in the first decade; to evolve toward CSR, reputation, corporate image, and purchase intention, in the second decade; and finally focused on ethics, purchase intention, consumer behavior, and attitudes, in the third decade.

Co-citation analysis
A co-citation analysis is described as "the scholarly contributions of authors who are frequently co-cited are likely to embody similar or related concepts" (Nerur et al., 2008, p. 321). Co-citation analysis can explain how referential frameworks of the Cause-Related Marketing field at different stages of its development affected evolutions in its general construction.

First phase for the period 1988-2000
Based on the co-citation analysis, for the period 1988-2000 (Fig. 5), it has been seen that there is predominately one cluster with a total 58 authors distributed in one cluster namely cluster -1 with red color (minimum of the documents for an author should 1 and minimum citation of an author should be 1).
There is a wide variety of authors cited in the papers on CRM in the first decade (but only once). Schurr is the only author who receives 2 citations in this decade.

Second phase for the period 2001-2010
According to co-citation analysis for the period 2001-2010 (Fig. 6), it has been noted that there are predominately two clusters with a total 1502 authors (minimum citation of an author should be 10 and the maximum citation of the author should be 24).

Third phase for the period 2011-2020
According to co-citation analysis for the period 2011-2020 (Fig. 7), it has been noted that there are predominately four clusters, with a total of 10,108 authors and 193 thresholds (minimum of the documents for an author should be 20 and minimum citation of an author should be 5; the maximum citation of the author should be 200).
In this analysis, we selected the five top co-authors who had the highest citation, such as Lafferty (200 citations In summary, the co-citation analysis shows that Lafferty is the most co-cited author in all time. And the next most co-cited authors are Mohr and Webb.

Cross-cultural analysis
Cultural norms and beliefs have a significant impact on shaping people's perceptions, attitudes, and behavior (Steenkamp, 2001). Lavack and Kropp (2003)  identified the research gap of cross-cultural studies in the field of CRM. Hence, they conducted the first cross-cultural research in the field of CRM by including four countries from different regions such as Australia (Oceania), Canada (North America), Korea (East Asia) and Norway (Europe), and investigated the consumers' role values towards the CRM. Since the third decade, more researchers have been participating and collaborating in cross-cultural studies. Table 5 details transversal research that has studied CRM comparing different countries.
According to the cross-sectional analysis, the nation has a different background of consumer and corporate cultures that varies from country to country. Sekaran (1983, p. 68) defined it as "Culturally normed behavior and patterns of socialization could often stem from a mix of religious beliefs, economic and political exigencies and so on. Sorting these out in a clear-cut fashion would be extremely difficult, if not totally impossible". Therefore, the scholars are taking more consideration in cross-cultural CRM study from the second decade. In this study, Table 5 shows that researchers from USA (i.e., North America) and South Korea (i.e., East Asia) studied together two times on culture analysis, one times with India (i.e., South Asia), and one time with Poland (i.e., Europe), one times with Philippines (i.e., East Asia) as well as China (i.e., East Asia). In addition, Italian researchers (i.e., Europe) studied one time on culture analysis with Japan (i.e., East Asia) and one time with Brazil (i.e., South America). Furthermore, India (i.e., South Asia) collaborated with Philippines (i.e., East Asia). Cross-cultural analysis in Table 5 shows that the researchers worked on four different cultures analysis rather than two cultures (i.e., Lavack & Kropp, 2003;and Schyvinck & Willem, 2019).

Country-wise development of CRM literature
Figure 8 reports regional (i.e., country-wise) participation of different researchers in the development of CRM literature. As this concept was introduced in the USA (Varadarajan and Menon, 1988), the studies from the first and second decades usually belonged to this geographical region. Thus, most of the research in CRM literature was published by researchers from US Universities: 92% of the contributions in the first decade (i.e., 12 research articles), and 40% (i.e., 30 research articles) in the second decade. However, some British researchers also contributed to CRM literature in the second decade, with 11% (i.e., 8 research articles) share of total CRM publications. Nevertheless, in the third decade, most of the CRM literature was published by Asian researchers. Hence, Indian researchers, with 9% (i.e., 24 research articles), and Taiwanese scholars, with 5% (i.e., 12 research articles), jointly published almost 14% of the articles in that decade. Although the American contributions fell to 33% (but only in relative terms, since in absolute terms they reached 85 research articles), their overall contribution remains the highest of all countries. And participation of British scholars was 6% (i.e., 15 research articles) in the third decade. In this Fig. 8, we
In this study, we observed that North American researchers are more involved in Cause-Related Marketing. This may be due to the importance that CRM has had in the USA since its inception, and the acceptance that CRM has had among American companies and consumers. Such as Cone (2010) showed, 88% of the American consumers supported the cause, 85% of the consumers had a good image of the company or product supporting a noble cause and cared about it, and 90% of the consumers demanded companies to find the right cause to support. More recently, another research also studied that 87% of American consumers would purchase a CRM product if the company supported the charitable cause (business2community, 2020).
The graphical presentation of the Time-Wise Development (see Fig. 1) shows 13 articles published until 2000 (first decade), 74 articles from 2001 to 2010 (second decade), and 257 articles from 2011 to 2020 (third decade). Natarajan et al. (2016, p. 248) and Thomas et al. (2020, p. 5) verified almost similar findings of the time-wise development from 1988 to 2016. But after that, the research on Cause-Related Marketing has abruptly increased in the last two years (2019-2020). We noticed that, in 2020, the researchers are more actively involved in the CRM field than the previous years to publish the research articles.
As observed in Fig. 8, the academicians and researchers from 37 different countries have significantly contributed to CRM studies. A large portion of CRM studies are conducted in two regions (i.e., North America and Europe). Thomas et al. (2020) shows similar results. Asian (i.e., Indian and Taiwanese) researchers have taken more interest in CRM and they have been publishing more and more articles since the third decade. On the other hand, we also noticed that the CRM topic was first introduced in Western societies (with Christian tradition). But after the first decade and during the second decade, CRM studies were also introduced in Muslim countries, such as Pakistan (1 research article) and Oman (1 research article). From the third decade, the researchers also explored other Muslim countries, such as Malaysia (5 research articles), Iran (4 research articles), Egypt (4 research articles), Turkey (3 research articles), Pakistan (3 research articles), Jordan (1 research article), Indonesia (1 research article), and Bangladesh (1 research article). So, in summary, we can highlight that researchers have been exploring the Muslim world in the field of CRM after the second decade.
And about the methodological development in CRM literature (see Fig. 9), the researchers have used more quantitative studies, compared to qualitative studies. Thomas et al. (2020, p. 7) also found a similar result. Thus, the trend seems to be for quantitative studies to continue to predominate over qualitative ones in the coming years, although mixed methods are experiencing slight growth. However, the combination of both types of studies, qualitative and quantitative, could offer more complete studies on CRM.
Lastly, Table 6 presents the journals involvement to publish CRM research articles. In our study, the key publications journals are International Table 6 The list of five most cited journals from each decade Our research also discovered different results from previous studies with respect to databases, partly due to the number of databases considered and the greater number of years analyzed in our study.

Conclusion
Cause-Related Marketing (CRM) is considered as an initiative that involves a donation to a specific cause, at a specific period of time, usually with a limited donation amount, and which depends on product sales and consumer behavior.
Therefore, the main objective of this study was to provide a comprehensive systematic review of the literature on CRM, categorizing each article by timewise development, country-wise development, methodological development, and role of journals. Cross-cultural analysis and bibliometric analysis were also included, as a new contribution of this research, in comparison to previous studies.
The main studies have been classified in three decades, which present significant differences. In the introductory decade (1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000), the field of CRM was introduced with limited published articles with the role of CRM in two different regions, such as North America, and Oceania.
First three Journals such as International Marketing Review, International Review on Public and Nonprofit Marketing, or Journal of Nonprofit and Public Sector Marketing, play a starring role to publish CRM research papers. In the emerging decade (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010), researchers explored more regions, such as East Asia, South Asia, and the Middle East. In this time frame, mix approach studies and cross-cultural studies were introduced for the first time in the field of CRM. And in the most thriving decade (2011-2020), scholars analyzed CRM in two more regions, such as North Africa and Sub-Saharan Africa. In this era, more scholars were interested in collaborating with other geographical regions such as North America and Europe. The number of published papers on CRM grew significantly.
However, this current study has some limitations. First, this research considered only two keywords: "Cause-Related Marketing" and "Cause Marketing". Thus, other terms might be also considered, such as "Social Cause" or "Cause-brand alliance". Secondly, the selection of the studies was limited only to the peer-reviewed journal research articles published in English. Maybe research articles in other languages could be also interesting. Thirdly, this current study just focuses on the full-text journal papers. Abstracts, theses, working papers, and conference proceedings were ignored. Fourthly, this study has used a limited number of databases to find the research articles: SAGE Journals, JSTOR, Emerald Insight, Springer, Wiley Online Library, Elsevier, Taylor & Francis Online, and Google Scholar. Other databases, such as EBSCO and ABI/INFORM, could have been also considered. Anyway, we also found different gaps in CRM research, so further research could be developed in these aspects. First, most academic scholars have largely focused on the developed countries, such as the USA and the UK, and less in developing countries (especially in the first and second decades). Although studies about CRM in developing countries increased in the third decade, the gap still exists. More studies are needed about developing countries because the researchers may find different results. In addition, more studies are also required to compare developed and developing countries, because researchers could find different interesting outcomes about CRM campaigns.
Secondly, the growing popularity of the internet and social media could be more considered by the companies, which could focus on digital marketing. Therefore, consumers could be more involved in a digital CRM campaign (Handa & Gupta, 2020). Only few studies have been conducted in this area, so the gap still exists, both in developing and developed countries.
Thirdly, various studies are conducted on the cross-culture context. But more research is needed to investigate the cross-cultural context, comparing developing and developed countries, and also Western and Eastern countries. Causes and consumer preferences or attitudes could be different from one country to another country.
Fourthly, few studies have been conducted in the mix approach (including qualitative and quantitative studies). More research is required for a better understanding of the mixed methodological approach in CRM. The most common and wellknown approaches to mixing methods are Triangulation Design, Embedded Design, the Explanatory Design, and the Exploratory Design. These methodologies could be discussed in CRM programs.
Fifthly, profit and non-profit organizations depend on each other in CRM campaigns. When both organizations develop CRM strategies, they can acquire risk. Few studies have been conducted on profit and non-profit organizations with CRM programs; therefore, this also needs to be discussed.
Finally, and according to Chéron et al. (2012), consumers positively view those CRM campaigns that take place for extended periods of time, and they might be disappointed with short duration campaigns. Thus, time frame of the CRM campaign can have a significant impact on the consumers' perception. Consequently, the campaign's time duration is another factor that is needed to be more discussed by researchers.

Varadarajan and Menon
The process of formulating and implementing marketing activities that are characterized by an offer from the firm to contribute a specified amount to a designated cause when consumers engage in revenue-providing exchanges that satisfy organizational and individual objectives.

1991
Smith and Alcorn Cause marketing may be the most creative and cost-effective product marketing strategy to evolve in years, and one that directly addresses the issue of measured financial returns.

Carringer
The joining together of a not-for-profit charity and a commercial company in an effort to raise funds and awareness for the cause while building the sales and awareness of the for-profit partner.

Pringle and Thompson
Activity by which a company with image, product or service to market builds a relationship with a "cause" or a number of "causes" for mutual benefit.  Cause-related marketing (CRM) is a promotional strategy that combines public relations and sponsorship strategies where a company makes a philanthropic commitment to a societal need or "cause" through a specific campaign that is promoted to and requires participation from consumers.

Galan-Ladero
Cause-Related Marketing is a CSR activity. It is an agreement between a company and a NPO to collaborate on a social cause and obtain, in this way, a mutual benefit. The company commitment is focused on contributing (financially or in kind) to the cause in terms of sales (the donation will depend, therefore, on consumer behavior). Normally, the campaign is conducted for a certain product, for a specific period, and with a particular NPO. Cause-related marketing is a marketing strategy wherein a product/brand/company is marketed in association with a "cause"-to change the behavior or donate a percentage of revenue for the betterment of society