Triple Method Approach to Development of a Genre-Based Approach to Teaching ESL/EFL Writing: A Systematic Literature Review by Bibliometric, Content, and Scientometric Analyses

In the last 19 years (2003–2021), research on genre-based approaches (GBAs) to writing pedagogy has been accumulating in the fields of English as a second language (ESL) and English as a foreign language (EFL). This review mapped existing literature to identify research trends and provide a research agenda for future GBAs. This study employed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and identified 52 published articles and 2 unpublished doctoral theses via a structured keyword search on Web of Science, Scopus, ERIC, Google Scholar, and ProQuest in the fields of teaching English to speakers of other languages, language learning, and education. The results show that GBA is now widely used in teaching English academic writing to ESL/EFL tertiary/graduate students. The main research findings include: (1) the top five countries in the number of paper publications are China (i.e., five), the United States (i.e., five), Japan (e.g., 4), Thailand (e.g., four), and Sweden (e.g., four); (2) the top four authors in the number of paper publications are Hyland (i.e., two), Lu (i.e., two), Negretti (i.e., two), and Pineh (i.e., two); and (3) the top three most strengthen keywords are writing pedagogy, genre-based approach, and English for academic purpose. This study also discusses the theoretical and practical implications.


Introduction
Genre-based pedagogy has been a hot topic since it was firstly introduced in the 1980s by John Swales in the area of English for Specific Purposes (Li, 2022;Swales, 1990). Now it is popular in language teaching and learning (Martin, 1992;McKnight, 2020;Zhang & Zhang, 2021), primarily in language education (Derewianka, 2003;Negretti, 2021). Some researchers have also employed genre-based pedagogy in studies on teaching writing in diverse discourses and on the effects of using a genre-based approach (GBA) to increase students' genre awareness (Carstens, 2009;Dong & Lu, 2020;Flowerdew, 2016;Giraldo, 2019;Guerra-Lyons & Mendinueta, 2020;Kuiper et al., 2017;Morell & Pastor Cesteros, 2019;Negretti, 2021;Tribble, 2017;Truong, 2017;Ye, 2020). Therefore, research on development of a GBAs to writing pedagogy may enhance students' English writing performance to the benefit of their development in English writing.
In the English as a second language and as a foreign language (ESL/EFL) context, the GBA has been widely used in teaching academic writing courses. In the GBA to English writing pedagogy, English language teachers provide clear instructions explaining linguistic characteristics and rhetorical patterns specific to the discourse in which students need to participate (Hyland, 2007). Teachers also explain genres' social-communicative purposes, structures, and language features (Hyland, 2003). With this instructional approach, English teachers help improve ESL/EFL students' understanding of textual significant articles were published on using a GBA in English Language Teaching and learning. However, in our review of these studies, we found that the main focus has been on writing courses, with only a few review articles (Derewianka, 2003;Li & Flowerdew, 2020;Paltridge, 2014).
Additionally, we found that published articles focused on GBAs are mainly quasi-experimental research articles or natural classroom-based longitudinal research articles (Almacıog˘lu & Okan, 2018;Humphries & Takeuchi, 2004;Khaw & Tan, 2020;Mauludin, 2020). Still, few review articles have been published. We searched websites of the leading Scopus indexed journals in teaching English to speakers of other languages (TESOL) and language learning and teaching to find exponential growth in the number of primary studies. Indeed, from 1979 to 2021, 54 preliminary studies were conducted on GBAs in teaching writing in the ESL/EFL context. However, after carefully searching leading academic publication databases, we found only one review article on a GBA in L2 writing instruction (Paltridge, 2014). This leading narrative review (Paltridge, 2014) showcased a holistic picture of GBAs' development from 1981 to 2014.
However, Paltridge (2014) mostly focused on GBAs' development in L1 writing, and (Cheng, 2021) argued that although numerous scholars are researching GBAs, review articles have blind spots in mapping existing knowledge. This situation has resulted in gaps in GBAs to teaching L2 writing and the need to identify its trends to help further develop the knowledge base. Unlike a traditional narrative review, a systematic literature review (SLR) is a replicable, scientific, and transparent process that can help collect all existing related publications to achieve specific research objectives (Mulrow, 1994). Thus, the current situation indicates great need for systematic, thorough review to map the GBA in L2 writing pedagogy studies and identify its trends in order to inform further practice and research (Lu, 2021). Therefore, this SLR sheds light on the GBA's development in L2 writing pedagogy studies because highquality review articles need to be published to showcase a broader picture of the GBA's development in writing pedagogy during the last 19 years (2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018)(2019)(2020)(2021).
Thus, a systematic, objective approach to scientometric analysis of the research literature is warranted to map existing articles and explore GBA trends in writing pedagogy. Such analysis is made possible by development of visualization technology, namely, CiteSpace. A scientometric analysis is a practical approach for performing reviews that evaluate a specific research focus's status quo and trends. It has the advantages of making full use of qualitative, quantitative, and computational approaches to assess and analyze research performance and development (Konur, 2012). A scientometric analysis is performed by evaluating publication years, authors, countries, keywords, abstracts, and so on. Numbers and frequencies are analyzed and visualized by using the information visualization software CiteSpace (Chen, 2006).
As an increasingly influential teaching approach, the GBA could benefit from an SLR that uses visualization techniques to identify themes and gaps in existing research. Therefore, this paper has two main objectives: To map existing GBA research published from 2003 to 2021 in the ESL/EFL context; and To use the findings to explore GBA studies' trends in writing pedagogy.

Research Methodology
We used triple analysis (i.e., bibliometric, content, and scientometric) and visual analytic techniques to achieve the two objectives. Cheng et al. (2018) investigated tourism and Safura Zabidin et al. (2020) examines both the status quo and the trend of Industry 4.0 applications from the construction engineering standpoint with the triple-approach analysis, but this study showcases a systematic, holistic, diachronic, and quantitative overview of GBA research, as represented in the domains of ESP and English for Academic Purposes (EAP), by reviewing the 54 selected articles from 2003 to 2021, mapping the status quo, and identifying research trends. We believe that such a scientometric review can provide a systematic account to complement existing studies and also contribute to GBA studies by answering the following two research questions: 1. What is the status quo of GBAs in writing pedagogy studies? 2. What are the trends of GBAs in writing pedagogy studies?
This review article combines an SLR and triple analysis (i.e., bibliometric, content, and scientometric), as shown in Figure 1. First, an SLR was conducted to collect data by selecting articles according to keywords, language, document types, and so on. Second, quantitative bibliometric analysis was employed to refine article selection and to explore GBA trends in writing pedagogy studies. Third, content analysis was used to describe selected papers in categorical terms. A careful review was conducted to map GBA research in ESL/EFL writing pedagogy studies. Finally, a scientometric analysis was performed by using the text-mining software tool CiteSpace (data visualization software) based on the theory of co-citation and a pathfinder algorithm invented by Chen Chaomei (Chen, 2006;Sabe et al., 2022). Its functions are co-citation, co-occurrence, and cooperative networks. Data analysis can be performed with databases such as the China National Knowledge Infrastructure, Chinese Social Sciences Citation Index, Web of Science (WoS), and Scopus (Chen, 2006;Sabe et al., 2022). This paper used CiteSpace to map and explore trends by country, institution, author, and keyword, to visually analyze the GBA in writing pedagogy studies, and to draw the science map for the last 19 years (2003-2021; details in Figure 1).

Systematic Literature Reviews
SLRs were initially used in academia as a systematic, transparent, and reproductive method of synthesizing research findings (Cook et al., 1997). The technique provides a comprehensive overview of existing literature related to specific research questions and to present and synthesize findings. Compared to a traditional literature review, an SLR is objective, systematic, transparent, and replicable (Mallett et al., 2012). SLRs began in the late 1970s when Cochrane (1999) provided practical guidelines for implementing SLRs in medical studies (as cited in Durach et al., 2017).
In recent years, SLRs have become popular for summarizing ''evidence-based practice'' in some educational research fields, such as e-learning (Valverde-Berrocoso et al., 2020), distance learning (Bashir & Warraich, 2020), and health care education (Madi et al., 2019). However, SLRs are scarce in teaching English as a second language (TESL) (Lu, 2021). Reasons might be the ''idiosyncrasies of each area, or the retrieval, identification, and synthesis of related articles'' (Evans & Benefield, 2001). Currently, SLRs are mainly designed for medical studies and require adjustment for their application in educational fields (Chong & Plonsky, 2021;Xiao & Watson, 2019).
An SLR contains four steps. First, clear and specific research questions must be proposed. Second, databases must be clearly defined by well-structured questions. Inclusion and exclusion criteria must be set by using prespecified research questions, definitions or conceptualizations, measures/key variables, research designs, participants, timeframes, and data (Xiao & Watson, 2019). Third, a thorough search for related articles should be conducted with minimal bias. Finally, all samples should be checked against predetermined criteria for findings related to the research questions (Xiao & Watson, 2019). In this regard, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) (2020) and Cochrane are two widely used systems that provide standardized methods. Samples are selected from a significant database and one or more supplementary databases to address bias issues (Xiao & Watson, 2019). Additionally, at least two individual researchers should review sample screening to avoid subjectivity (Chong & Plonsky, 2021;Xiao & Watson, 2019). The current study followed PRISMA (2020) guidelines to conduct the SLR.

Systematic Literature Review in this Study
This study conducted an SLR by focusing on trends (during the last 19 years from 2003 to 2021), on existing GBA research in the ESL/EFL context, and on research gaps in recent writing pedagogy studies. Setting a timeframe is vital to conducting a systematic literature review (Major & Savin-Baden, 2010). We selected 2003 as the starting point of the timeframe for the following reasons: First, Professor Dr. Ken Hyland's seminal article, Genre-based pedagogies: A social response to the process, was published in 2003. He is affiliated with the University of East Anglia, United Kingdom, and was the first to compare genre-based and process-based writing instruction in L2 writing classrooms. As of August 2022, Hyland's (2004Hyland's ( , 2007Hyland's ( , 2008Hyland's ( , 2015Hyland's ( , 2016Hyland's ( , 2021 paper has been cited 1,575 times according to Google Scholar. Thus, his paper is among the most prominent in the GBAs in L2 writing. Notably, in his subsequent work on GBAs in L2 writing, he developed many of the themes presented in this article.
Hyland's paper was published 19 years ago; thus, conducting an SLR of research conducted since then will reveal the key works that have influenced and shaped genre and genre-based teaching in L2 writing in English in classroom settings. During the first round, each study's research type, subject, objectives, and methods were reviewed by preset inclusion and exclusion criteria by careful screening of selected articles' titles, abstracts, and keywords. If these components were unclear, then full articles were read. A common method of conducting an SLR in diverse research fields, PRISMA requires four steps: identification, screening, eligibility, and data abstraction and analysis, detailed below.
Identification. The identification process was performed in December 2021. In this phase, 56 articles from Scopus, 50 from WoS, 3,486 from ERIC, 24,500 from Google-Scholar, and 52,289 dissertations/theses from ProQuest were carefully selected.
Screening. The screening phase included or excluded articles by preset criteria (Table 1). Eligibility, inclusion, and exclusion criteria were determined to select articles that met the SLR's requirements (Table 1).
Eligibility. In the third phase, articles were included or excluded according to the preset criteria. Excluded from the databases in this phase were 22 similar articles, but 88 articles remained. According to the GBA and the inclusion and exclusion criteria, 54 articles were finally selected as relevant to the GBA in writing pedagogy.
Data abstraction and analysis. During the final phase of data abstraction and analysis, all articles were evaluated, reviewed, and analyzed. We selected 54 articles for this study (Table 2) shown in Appendix A. The SLR procedure is shown in Table 2.  Zhai et al., 2022).

Criteria Inclusion Exclusion
Publication timeline

Bibliometric Analysis in this Study
To identify the essence of a field, bibliometrics, including citation and co-citation analyses, uses quantitative methods based on written documents (McBurney & Novak, 2002). The field of TESOL has embraced bibliometric analysis; thus, its use has increased (Ngoc & Barrot, 2022;Pearson, 2022;Yilmaz et al., 2022). The specific reasons for this increase are the advancement, increased availability, and increased accessibility of scientific databases (e.g., WoS, Scopus, ERIC, Google Scholar, and ProQuest). In addition, using bibliometric analyses in TESOL is not a fad but a reflection of their ability to manage large volumes of data and produce high-quality results. Using SLR data, we applied bibliometric analysis to quantitatively analyze published papers and unpublished theses closely related to this study. As shown in Table 2, 52 articles and 2 theses from the SLR that were strongly related were analyzed. This technique was conducted to obtain an overview of the descriptive data such as year, country, research discipline, and trends in publication. An outline of the bibliometric analysis is presented in Figure 2.

Content Analysis in this Study
The importance of references differs in bibliometric analyses, and citations can be unrelated within a publication or article (McBurney & Novak, 2002). Citation patterns tend to be reduced by a sufficiently large sample (Schildt et al., 2006), but references continue to reveal the thoughts and concepts behind a publication. In this study, content analyses of focal articles were conducted to overcome these limitations (Krippendorff, 2018) and provide a direct, comprehensive overview of the topics and themes related to GBAs. Specifically, content analysis was conducted on the abstracts of 54 GBA primary studies conducted between 2003 and 2021 in three fields: TESOL, language learning, and education. Three themes emerged: types of writing tasks, research design/methods, and participant demographics.

Scientometric Analysis in this Study
Scientometric analysis visualizes bibliometric networks to create thematic mappings of special disciplines, science domains, and research frameworks derived from comprehensive bodies of literature (Chen, 2006;Sabe et al., 2022). Manual reviews provide insightful overviews of the field but are prone to bias and interpreted subjectively (Chen, 2006). Thus, in this paper, we used CiteSpace for scientometric analysis. CiteSpace is a Java tool for analyzing co-citation networks (Chen, 2006;Sabe et al., 2022). The software provides unique advantages for visualizing and analyzing scientific literature, thereby facilitating the understanding of the literature by creating accessible graphs that uncover implications hidden in a vast amount of data (Chen, 2006;Liu & Hu, 2021;Sabe et al., 2022). We used this innovative visualization technique for the analysis and visualization of a broader network from Scopus. Figure 6 shows our data mining process. During scientometric analysis, the 43 Scopus articles were reviewed to visualize bibliometric networks for mapping the GBA's trend in writing pedagogy studies from 2003 to 2021. Using CiteSpace, the extensive network from Scopus was analyzed and displayed. The 43 records were considered the research data, as outlined in the CiteSpace manual. As a result, the following three scientometric techniques were performed: (1) Co-author analysis: a co-occurrence network of authors and countries, reflecting micro-and macro-level collaboration; (2) co-words analysis: a network of keyword co-occurrences and keyword evolutions; and (3) co-citation analysis: to identify co-cited journals, co-cited authors, and co-cited documents.
Overall, the three approaches-bibliometric, content, and scientometric analyses-complement each other when identifying key concepts and themes, uncovering research gaps, setting areas for future research, and establishing the theoretical foundations and structure of GBAs studies (Donthu et al., 2021). Using network-based citation analyses, we robustly demonstrated the structure and knowledge base of GBA studies. Researchers can gain detailed conceptual insights by analyzing the texts authors use rather than merely authors' citations. Our use of a triple-approach analysis quantitative systematic review helped map the status quo and identify trends in GBA studies, thereby providing a more systematic, objective, and holistic overview of GBA studies than has been available in the literature. Moreover, this TESOL study is the first to use three methods that complement each other in an integrated, objective, and accountable fashion, thereby reducing bias associated with traditional literature reviews and expert interviews in TESOL (Gough et al., 2017).

Bibliometric Analysis
We used bibliometric analysis to review 52 previously published articles and 2 unpublished doctoral theses based on SLR data. This quantitative technique allows a holistic overview to obtain descriptive data, such as the year, country/region, research discipline, and author (Cheng et al., 2018;Donthu et al., 2021;Qureshi et al., 2020) (see outline in Figure 2).
Publication year map and trend. Figure 3 shows the publication year trend for the GBA in writing pedagogy studies from January 2003 to December 2021. Studies peaked in 2020 with 11 published articles. Figure 3 evidences that most work on GBAs was undertaken within the last 5 years (e.g., 2017-2021). In contrast, research productivity in previous years was extremely low, at approximately one paper per year from 2003 to 2016 and that the GBA in writing pedagogy studies has not developed progressively during the past 19 years. In 2017, seven papers focused on this topic in the ESL/EFL context. In 2018 and 2021, the numbers were 8 and 6, respectively. In 2019, only one article was published, less than the average of the previous 5 years (2017)(2018)(2019)(2020)(2021). Findings from bibliometric research on annual publication trends indicated the GBA's equal distribution of publications and positive development, with an average of 6.6 publications for the last 5 years (2017-2021). However, minor fluctuations occurred (see Figure 3). Therefore, we call for more publications on the GBA in writing pedagogy studies, especially in ESL/EFL.
Publication distribution by country/region map and trend. Figure 4 shows that China (e.g., five) and the United States (e.g., five) produced most of the articles on the GBA in writing pedagogy during the past 19 years, followed by Japan (e.g., 4), Thailand (e.g., 4), Sweden (e.g., four), and Hong Kong (e.g., three). Meanwhile, the Association of Southeast Asian Nations (ASEAN), specifically Malaysia (e.g., two), and Indonesia (e.g., two), also contributed (Cullip, 2009;Emilia, 2005;Mauludin, 2020;Phan & Ganapathy, 2020). However, the GBA's birthplace, Australia, produced only two articles during the research period (Khaw & Tan, 2020). A possible reason might be global collaboration since many GBA scholars have researched countries other than their own. Figure 4 shows publications by country/region (details by the Flourish visualization tool shown in Figure 4 The results of the bibliometric research regarding country/region distributions support Hyland and Jiang (2021), that is, the United States has dominated the scholarly publishing industry, owing to substantial investments in science, technology, and education. Our findings are also supported by Alinasab et al. (2021), who found that genre-based writing instruction in nonnative English speaking countries has received insufficient empirical attention. Thus, although the GBA has been used worldwide, their use in L2 writing has not been widespread (Alinasab et al., 2021).
Notably, the reason that China (e.g., five) produced the most articles on GBAs in writing pedagogy during the past 19 years might be its 2013 educational policy concerning EAP, implemented by the Shanghai Education Bureau (2013). Since then, China's EAP scholars have focused on genre-based instruction in writing classes at the nation's universities (Li & Wang, 2018). This result is supported by Hyland and Jiang (2021) that China has become an emerging center for EAP research. Another possible explanation for this phenomenon is that the Chinese government has increased funding and support for research (Zhang et al., 2013). Therefore, in China, a language policy should be developed that promotes EAP education, and worldwide, improvements in genre-based writing instructions are necessary.
Author map and trend. From the Scopus database, 43 articles were selected based on our aforementioned criteria. Among these articles, four authors significantly contributed to the GBA in writing pedagogy studies: Hyland (2003Hyland ( , 2007, Lu et al. (2020), Lu, Casal et al. (2021), Negretti and McGath (2018), Negretti (2021), Jodairi , and Jodairi Pineh (2017) each published two works. Other scholars' trend was also constant, with only one publication each (Table 4), so an increased number of scholars are needed to research the GBA in writing pedagogy. Given the topic's importance and potential, we believe that more authors should be writing on the GBA in the ESL/EFL field.
In addition to the four prominent authors, Hyland is a well-known ESP scholar with over 30 significant books, 240 journal articles, and book chapters in the ESP field. He is also the co-founder of an SSCI indexed journal: Journal of English for Academic Purposes. Hyland's seminal publication in 2003, titled Genre-based pedagogies: A social response, has had a substantial effect on writing pedagogy, especially second language writing, and increased the teacher-friendliness of writing lessons. Additionally, Hyland has taught L2 writing in Sudan, Saudi Arabia, Malaysia, Papua New Guinea, New Zealand, and Hong Kong and significantly contributed to the development of L2 writing pedagogy. He (https://uea. academia.edu/KenHyland/CurriculumVitae) is among the top 0.5% of scholars on ResarchGate and Academia.com.
Another leading scholar, Professor Xiaofei Lu, from Pennsylvania State University, USA, is an expert in corpus linguistics, second language writing, and EAP. Lu has contributed to the integration of GBAs with corpus analysis into academic writing pedagogy , focusing on the linguistic realizations of rhetorical and communicative functions in academic writing genres

Content Analysis
To map existing GBA research and identify its trends in the ESL/EFL context, we performed content analysis on the 54 selected articles, classifying them into three major themes: (1) types of writing tasks, (2) demographics of research participants, and (3) research design and/or methods ( Figure 5).
Research design map and trend. Of the 54 selected articles, 12 employed qualitative research methods to investigate perspectives of teachers, students, or both (Abdel-Malek, 2019; Almacıog˘lu & Okan, 2018;Andre & Schneider, 2004;Giraldo, 2019;Heron & Corradini, 2020;Kindenberg, 2022;Mingsakoon & Srinon, 2018;Mizumoto et al., 2017;Negretti, 2021;Negretti & McGrath, 2018;Tribble, 2017;Xeketwana, 2018). As research methods, the majority of these studies employed semi-structured interviews or focus group discussions. They also employed case study research designs focusing on attitudes and beliefs of teachers, students, or scholars on application of the GBA in writing curricula. Other research methods were also adopted, for instance, experimental/quasi-experimental (Carstens, 2009;Changpueng, 2012;Mauludin, 2020;Meyer et al., 1987;Phan & Ganapathy, 2020). In this method, researchers usually divided student participants into one to four treatment/experimental groups who received various GBA instructional strategies and, in general, a control group who did not receive any strategies, in order to examine how the GBA was applied to enhance writing competence.
Furthermore, these countries had fragile collaborative connections; even so, some pooled connections revealed international collaborations: cooperative networks between China and the United States, between England and Sweden, between the Netherlands and Belgium, and between Australia and Hong Kong (Dong & Lu, 2020;Kuiper et al., 2017;Mahboob, 2014;Negretti, 2021). Earlier published articles (De Oliveira & Richardson, 2001;Rezaeian, 2015) have suggested that cooperation between native and nonnative English speaking educators, researchers, and authors can enhance the quality of publications in English (details in Figure 7). Therefore, this field requires a considerable number of collaborative networks.
Network map of keyword co-occurrence and evolution analysis. Keywords can identify a research article's topic, and keyword co-occurrence networks can help investigate hot topics in a specific field during a specific period (Su & Lee, 2010 ). Moreover, an evolution network can demonstrate the knowledge area's development during a specific period. Figure 8 shows that the keyword cooccurrence network of research on the GBA in the writing pedagogy studies includes 162 nodes and 485 links. Moreover, keyword occurrence frequency identifies the node's size. The top 11 keywords in frequency were: genre pedagogy (11), academic writing (8), genre analysis (5), genre (5), genre-based pedagogy (5), systemic functional linguistics (4), student (5), writing (4), writing pedagogy (3), GBAs (3), and narrative (2). This indicates that numerous scholars paid attention to genre pedagogy and writing studies and that most studies were from a systematic functional linguistics perspective. Finally, keywords with high betweenness centrality reveal hot topics. In this SLR, three keywords received relatively high betweenness centrality scores, specifically, ''academic writing'' (0.51), ''English for research publication purpose'' (0.44), and ''genre awareness'' (0.34) (details in Figure 8).
Using keywords to detect ''citation bursts'' not only identifies the research focus but also makes the research frontier visible (Wu et al., 2020). Citation bursts in publications are generally indicative of noteworthy increases in a research field. Keyword citation bursts can reveal emerging topics in a field during a specific period (Wu et al., 2020).We identified the 25 most strengthened keywords from 2003 to 2021. A list of 25 keywords (Table 5) with high citation bursts in different periods and research topics and changes, is also shown in Figure 9. When each keyword first appeared and their durations of influence on the research area were observed (Wu et al., 2020). In Figure 9, the blue line denotes the entire study period (2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018)(2019)(2020)(2021), and the red line denotes the citation burst (Wu et al., 2020). We divided the development period into two phases (i.e., 2003-2013 and 2014-2021) to precisely detect research topics within the ''genre-based approach'' and identify the trend in their development in L2 writing between 2003 and 2021.
2003 to 2013: Responding to process-based writing instruction. As is shown, most of the keywords in the period 2003 to 2013, such as ''writing pedagogy'' (1.2136), ''genre-based approach'' (1.1705), ''genre-based writing instruction'' (0.8434), ''genre'' (0.7412), ''second language writing pedagogy'' (0.6837), and ''process-writing'' (0.679) had a longer burst duration than the keywords in the second research period. During this first period, the focus of research on writing instructions shifted from a process-based approach to a GBAs informed by systemic functional linguistics (SFL), which may explain this phenomenon. Moreover, the interest in genre pedagogy in L2 writing increased because of the improved understanding of how language is structured to accomplish social purposes (Hyland, 2003). Studies related to these keywords may be considered pioneering in the GBA. They have provided important, fundamental sources for the use of GBAs in L2 writing as well as new research directions.
Specifically, Hyland's seminal article published in 2003 compared genre-based and process-based writing instruction in L2 writing classrooms and thus promoted the development of GBAs in L2 writing. Articles, books, and book chapters on the use of GBAs in L2 writing were published during the studied period (e.g., Carstens, 2009;Emilia, 2005;Firkins et al., 2007;Humphries & Takeuchi, 2004).Furthermore, findings indicated the emerging research focus of GBAs might be its use in L2 writing for teachers from nonnative English speaking countries worldwide (Cheng, 2021). (0.6742), and ''esl writing'' (0.6742) were also hot topics for GBA scholars in this period. The findings reveal that most GBA scholars conducted action research to examine GBAs' interactions with students in L2 writing classes (Cheng, 2021). Furthermore, these findings reflect that GBAs aim to examine the social function of language and linguistic features of genres that assist in this function (Cheng, 2021;Hyland, 2003Hyland, , 2007. 2014 to 2021: Flourishing in EAP/ESP field. As shown, most of the keywords in the period 2014 to 2021, such as ''English for academic purposes'' (0.9768), ''EAP'' (0.9768), ''academic writing'' (0.8783), and ''genre analysis'' (0.7898), could be viewed as hot topics during this period, even a major frontier of GBAs, because their burst duration has lasted until now. As a result of the findings, the second stage is called ''Flourishing in EAP/ ESP.'' According to Liu and Hu (2021), the 2000s-present period can be considered the flourishing period for the development of English for Specific Purposes/ English for Academic Purposes. It seems that the findings are consistent with those made by prominent figures in the study of GBAs, including Cheng (2021), Hyland (2015Hyland ( , 2007, Swales (2019), and Tardy et al. (2022). It was found that genre-based writing instruction was very popular in EAP/ESP classrooms. The phenomenon might be caused by the fact that most L2 teachers are familiar with ESP/EAP's GBAs (Cheng, 2021).As these findings demonstrate, John Swales' seminal work Genre Analysis has had an enormous impact on EAP genrebased pedagogies.
Consequently, these findings highlight an urgent need for effective EAP/ESP GBAs teaching methods in L2 writing classrooms. The CARS model by Swales (1990) and the teaching learning cycle developed by the Sydney School (Feez & Joyce, 1998) were Western-created approaches and unlikely to be appropriate for L2 teachers outside of Western contexts (Cheng, 2021). Nevertheless, these studies demonstrate that the two models have had a significant influence on L2 writing, and we should acknowledge the great contributions these leading figures have made.
Next, we identified research hotspots' evolution by period of keywords through co-occurrence links ( Figure 11). Lines connect nodes that depict cooccurrences between keywords, and colors associated with these lines indicate when new connections were established. Considering the transition of GBAs from native English speaking to nonnative English speaking settings, keywords have migrated away from ''social literacy'' to ''academic literacy,'' ''academic biliteracy,'' and ''biliteracy.'' A growing number of researchers have become interested in ''writing pedagogy,'' ''genre-based approaches,'' and ''academic writing'' since 2015. By contrast, this field witnessed many frequently emerging concepts: in 2016 ''English for research publication purpose,'' ''scientific writing,'' ''English for academic purpose,'' ''second language writing,'' and ''academic writing'' indicated increased scholarly attention; in 2017, ''corpus'' signaled integration of other theories with GBA; in 2018, ''English as a lingua franca'' showed GBA's acceptance and use worldwide; in 2019, ''college English'' indicated its use in tertiary writing courses; in 2020, ''EAP materials and task design'' indicated its practical approach in EAP writing courses; in 2021, the dominant keyword was ''writing performance.'' In brief, during the last 19 years, the GBA has been increasingly developed to improve English writing pedagogy and student performance (details in Figure 10). The findings indicate that scholars have devoted the most attention to EAP and genre pedagogy studies. Therefore, scholars from the EAP field have made significant contributions to the development of GBA in writing pedagogy; furthermore, an increasing number of scholars have focused on its application in TESOL. However, further research is necessary.

Implications for Future Research and Practice
The research results of our triple-approach systematic review provide certain theoretical and pedagogical implications as well as recommendations for future research on GBAs in the L2 writing field. From theoretical perspectives, this study reaffirms Lu et al.'s assumption that there is a new trend of integrating related theories, including data-driven learning (Mizumoto et al., 2017),  ( self-efficacy (Zhang, 2018), and corpus analysis , into genre analysis theory in GBA studies. Particularly, this study confirms that other theories can be integrated into the EAP writing classroom, especially in the ESL/EFL setting. Hence, we suggest further research on the effectiveness of hybridizing GBAs in L2 writing classrooms to provide alternative strategies for L2 writing teachers. From pedagogical perspectives, this systematic review allows L2 teachers to identify, for example, which authors have provided the most effective writing instruction in L2 writing, which country produces the most GBAs, and the most innovative GBA writing instructions. For future research, we suggest that researchers should pay more attention to this field because English academic writing competence is becoming increasingly significant for ESL/EFL learners at the tertiary/graduate levels because students from nonnative English speaking countries increasingly need to pursue higher degrees in English (Carstens, 2008;Mehar Singh, 2018). However, research remains scarce for instruction at the tertiary/graduate level. For this reason, much research in the academic writing field has been conducted to help improve ESL/EFL learners' English writing competence in scholarly research articles (Corcoran & Englander, 2016;Li & Flowerdew, 2020). Still, more research is needed on GBA applications in English academic writing to sustain development of ESL/EFL tertiary/graduate students' skills. The few existing studies focus mainly on students in the sciences, with very little attention to students in the social sciences (Dovey, 2010;Hasyim et al., 2020;Hsu & Liu, 2019;Li & Flowerdew, 2020;Lu, 2021).Consequently, more robust research and empirical support in social science disciplines are needed in future studies. To maintain minimal bias, this study employed an SLR with a triple analysis (i.e., bibliometric, content, and scientometric). However, the research has some limitations, primarily in inclusion/exclusion criteria for the SLR process. Further investigations could include books and/or non-peer-reviewed articles to showcase a more comprehensive picture of the GBA in writing pedagogy. In contrast, future scholars could narrow the research scope by focusing on the GBA in English academic research articles to provide support for improved English academic writing competence. Furthermore, the period for selecting articles could be extended to include 1979 to the present to provide a view of GBAs' development and better identify its trends. Overall, the current research serves as a basis for further investigation.

Conclusion and Final Notes
To our knowledge, this is the first review to use tripleapproach analysis to capture the status quo and identify trends in GBA research in L2 writing classrooms. This study's research objective was, first, to map GBA research and, second, to identify its trends in writing pedagogy in the ESL/EFL context during the period 2003 to 2021. To achieve these objectives, we performed a triple analysis SLR to review selected articles from the domains of country/region distributions, authors, research disciplines, writing tasks, research design/processes, research participants, annual publication trends, keyword bursts, and co-occurrences of keywords to demonstrate research trends (details in Figure 11).
To achieve the first objective, findings indicated that GBAs are now worldwide used, specifically, the top six countries publishing GBA writing pedagogy studies were China, the United States, Japan, Thailand, Sweden, and Hong Kong. Analysis of research disciplines showed that although most studies were produced in the social sciences and arts and humanities, some contributions were from psychology, business management and accounting, computer science, and engineering. In other words, the GBA is now widely used in a variety of disciplines. Meanwhile, analysis of writing tasks revealed that the GBA could be used to teach recounts, research articles, narratives, critical literacy, and professional reflective writing, as well as for test purposes with positive outcomes. Analysis of research designs and methods identifies a wave of the GBA in writing pedagogy studies. The quasi-experimental research design dominates this field by focusing on the GBA's effectiveness in writing pedagogy from the perspectives of teachers, students, and scholars. It is evident from participant analysis that the majority of students in the GBA were tertiary students, with some research focusing on master's and doctoral students, showing that the GBA is now widely used in higher education institutions for teaching writing.
To achieve the second objective, we performed triple analysis to review articles from the perspectives of annual publication trends, keyword bursts, and keywords' co-occurrence. Findings from bibliometric research on annual publication trends indicated the GBA's equal distribution of publications and positive, sustainable development for the last 5 years (2017-2021). Furthermore, we performed a scientometric-assisted review of 43 articles from the Scopus database by using CiteSpace to visualize GBA research trends via keyword burst and keywords' co-occurrence. Keywords were also utilized to establish the occurrence network to reveal hot topics from 2003 to 2021. Additionally, the time factor was studied to identify keyword evolution, revealing that the three most frequently used keywords were ''academic writing,'' ''English for research publication purpose,'' and ''genre awareness.'' In scientometric analysis, CiteSpace software crystallized GBA related research's significant research findings. In this regard, however, we call for more publications on the GBA in writing pedagogy studies, especially in ESL/EFL.
In this SLR, we traced the history of genre-based pedagogy (e.g., 2003-2021) for teaching ESL/EFL writing through crucial and influential work in its development. The majority of the work included is practical, focusing on introducing and teaching multiple genres. However, a few theoretical articles contribute to the notion of how to think about genre and how to conduct research on genre. Because this study is mainly concerned with ESL/EFL writing, it refers particularly to ESP and Australian SFL genre studies. North American New Rhetoric Studies is also included. However, the focus was originally on L1 writing studies. More recently, it has expanded to include academic writing as well, as demonstrated by the SLR entries.
Because we focused mainly on empirical research in ESL/EFL settings, in closing, we apologize for omission of some noteworthy books, reviews, and articles related to GBAs. Furthermore, SLR allows only a limited number of entries, making it difficult to include fully comprehensive materials.

Acknowledgments
We would like to express our great appreciation to Professor Dr. Ken Hyland for his valuable and constructive suggestions during the revision of this systematic literature review article. His willingness to generously give his valuable time has been very much appreciated. We conducted this study to understand better Genre Based Approaches (GBAs) development in recent 19 years. We are also extremely grateful to the reviewers for reading and providing constructive feedback on earlier articles.

Author Contributions
All authors contributed to several aspects of the study, specifically, conceptualization, X.

Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.