A Bibliometric Review of Research on STEM Education in ASEAN: Science Mapping the Literature in Scopus Database, 2000 to 2019

In recent years, Science, Technology, Engineering, and Math (STEM) education has become important in many countries around the world. In this study a bibliometric analysis was applied to evaluate the scientific results of STEM education in the Association of Southeast Asian Nations (ASEAN) region, indexed in the Scopus database for the period 2000-2019. A total of 175 publications were taken from the Scopus database for analysis. Our main findings show that the trend of research in this field has shown a dramatic increase in scientific production in the last three years, when the published amount accounted for 67.43% of the collection. Authors with the most publications came from the top 10 universities and research institutes (accounting for 38.44%). Scholars in the ASEAN region tend to submit their works to Q3 and Q4 journals in the SCImago database. Diverse research with cross-cutting topics focus on STEM for undergraduate students,


INTRODUCTION
STEM education is an interdisciplinary approach in the learning process, in which the principle academic concepts are integrated with real-world lessons. STEM education helps students apply their knowledge in science, technology, engineering and mathematics into specific contexts, helping to connect schools, communities, workplaces and global organizations, thereby developing STEM capabilities for competition in the new economy (Hsu & Fang, 2019;Le et al., 2019). The development of STEM education has a positive impact on academic achievement and the development of various skills for students (Batdi et al., 2019). In recent years, STEM education has become both important in many countries around the world and the concern of many policymakers. In many countries, the economic and social benefits of scientific thinking and STEM education are widely believed to have broad applications for workers in both STEM and non-STEM occupations. As such, many contemporary policymakers consider widespread STEM literacy, as well as specific STEM expertise, to be critical human capital competencies for a 21st-century economy (Gonzalez & Kuenzi, 2014;Hsu & Fang, 2019).
The basic bibliometric analysis uses descriptive statistics to document "topographical" trends within a body of knowledge (Hallinger & Kovačević, 2019) . In recent years there have been researches on scientific bibliometric analysis of STEM education in the world via the Web of Science database (Aksoy, 2018;Batdi et al., 2019;Özkaya, 2019;Yu et al., 2016). These researches have drawn a complete picture of the formation and development of STEM education's researches and applications. There has been a rapid increase in the number of STEM education researches during the previous decade; Academic interest in STEM in education rocketed after 2008 (93.3% of the publications 2 / 11 related to STEM education were formed by the works published between 2008-2017). It can be seen that the countries that contributed most to STEM education during 1992-2013 were developed countries: The United States, England, The Netherlands, Australia (Özkaya, 2019;Yu et al., 2016). Of these, the US is the nation that realized the highest number of collaborations with other countries, while England is guiding the researches that will be made in the STEM education subject area (Özkaya, 2019). This can be explained partly by the increasing number and funding of STEM education projects in the US (a total of 127 projects funded by the US Department of Education's Institute of Educational Sciences (IES) from 2003 to 2019) (Li et al., 2020). STEM educational publications mainly focus on Q1 journals in the SCImago database, such as the International Journal of Science Education, the Journal of Science Education and Technology, the Journal of Engineering Education, and teachers' college records with the STEM keywords: science education, STEM education, and higher education (Özkaya, 2019;Yu et al., 2016).
The Association of South East Asian Nations (ASEAN) was established on August 8, 1967 in Bangkok by the five original member states: Indonesia, Malaysia, Philippines, Singapore, and Thailand. Today, the membership includes 10 States: Brunei Darussalam, Cambodia, Indonesia, Laos, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Vietnam, in addition to one Observer -Papua New Guinea. ASEAN researches have attracted the attention and scholarly debate of both regional and international scholars, but academic researches on ASEAN are limited because research parameters are always locked in issues related to economy, politics, security, and trade development in the region. The issue of education in the ASEAN region is a subject of little research (Koh, 2007).
From the previous researches, it can be seen that the research on STEM education has increased sharply in recent years in developed countries and has had a positive impact on the development of student's skills to meet the needs of highly skilled labor (Friedman, 2005;Halim et al., 2018;Promjan & Ditcharoen, 2019). However, previous studies have not mentioned the importance of STEM education research in the ASEAN region. Therefore, the main objective of this study is to explore the current state of STEM education research in ASEAN countries by using bibliographic data extracted from the Scopus database from 2000 to 2019. This study is to answer the following questions. Results from this study provide information that may be useful for research institutions in ASEAN countries. It is also especially relevant for decision makers preparing future plans and grants to support the development of STEM education research in the ASEAN region for the purpose of meeting international quality.
In the study design stage our main research question was: What was the bibliometric of publications in STEM Education, which were published by scholars with ASEAN affiliations, and indexed in the Scopus database for the 2000-2019 period.
Data collection stage is divided into three sub-stages: data collection, data filtering, and data cleaning.
Step 1: Data Collection. The author team performed a search from the Scopus database (http://www.scopus.com) with advanced search options to ensure search terms and operators matched the syntax of the search tool.
Affiliation Country is defined as all ASEAN member countries; Year of Publication was selected in the period from 2000 to 2019.
Searching keyword for the field of STEM education included: STEM or a combination of words (educat* OR learn* OR teach*) and words (science* AND technolog* AND engineer* AND mathematic*). The symbol "*" represents any group of characters in the Scopus data search syntax. Search is limited to summary, keywords, and document titles. Document types are limited to: articles, conference papers, and reviews in the field of social sciences, written in English.
Query strings query data through Scopus as follows: AFFILCOUNTRY ("Viet nam" OR vietnam OR singapore OR brunei OR malaysia OR thailand OR philippines OR indonesia OR laos OR myanmar OR

Contribution to the literature
• Overview of the development of research in STEM education in ASEAN.
• The collaboration of STEM education researchers in the ASEAN region.
Step 2: Data Filtering. We conducted data filtering by censoring titles, abstracts, and keywords, removing materials that are not related to STEM education. After filtering the data, the number of remaining records was 175. With this list, we conducted initial analysis on tools provided by Scopus to collect additional information about authors, affiliations, and journals. For further analysis we extracted the information from the search results into CSV format (file .csv) and Bitext (file .bib) to perform analysis on bibliometric tools.
Step 3: Data Cleaning. Downloaded data needed to be cleaned because the quality of analysis depends very much on the quality of input data. Some data errors have been corrected in this extra period. For example, "Viet nam" and "Vietnam" were corrected as one country, "Universiti Kebangsaan Malaysia" and "Kembangan Malaysia University" were corrected as one affiliation, etc.
Measurements were conducted on this data. Various analytical techniques have been applied to extract the information about the collection of publications. General statistics provide quantitative information such as the number of annual publications and publication trends, journals with the top number of publications, and authors or organizations with the highest productivity. Co-authoring across countries has been analyzed to research the collaboration among the most productive countries in the field of research. Synonym analysis of keywords, titles, and abstracts was conducted to identify the most important research topics and trends. Many tools were used in the data visualization stage. The most used software programs were BibExcel (Persson, 2009) (Cobo et al., 2012), and Bibliometrix (Aria & Cuccurullo, 2017).
To analyze the data obtained in this paper two main software programs were used: Bibliometrix and VOSviewer. In addition, Microsoft Excel was used to summarize data in different stages. A website that runs Scopus data to calculate two metrics (SCImago Journal Rank (SJR) and Source Normalized Impact per Paper (SNIP)) was also used, which was directly compared to Web of Knowledge's Impact Factor: (https://www.scimagojr.com/) to analyze the quality of journals.

Contribution by Nations
The total number of documents listed is 175, of which ASEAN countries have contributed according to their number of articles as follows: Malaysia (83); Thailand (35); Indonesia (24); Singapore (23); Philippines (10); Vietnam (4) and Cambodia (1). In this list, there are no authors from Brunei Darussalam, Laos, or Myanmar (The number of articles is counted for the country or research organization if the article was conducted by one or more authors from such country or organization, regardless of how many co-authors were not belonging to that organization or country). Figure 2 shows the number of articles by country (from 2011 to 2019) in the field of STEM education. It can be seen that Malaysia has a remarkable contribution compared to the rest of the region in this field. The number of publications on this topic increases annually (except for 2016). Thailand and Singapore are also countries that frequently pay attention to this topic when there are annual publications, however, their numbers only increased modestly. Other nations have also researched STEM education but their contributions are not continuous. The year 2019 recorded the largest number of publications, by country respectively: Malaysia (30), Indonesia (12), Thailand (9), Philippines (6), Singapore (5) and Vietnam (2).
The academic cooperation on STEM education research among ASEAN countries and other countries in the world is shown in Figure 3. For each of the 26 countries, the total strength of the co-authorship links with other countries will be calculated. The countries with the greatest total link strength will be selected. As the diagram shows Malaysia has the most publications and has research cooperation in the field of STEM education with many other countries such as: Indonesia, the United States, Australia, and the Czech Republic. The authors from Thailand and Singapore cooperate mainly with authors from the United States in addition to some few other countries.  The collaboration between STEM affiliations in ASEAN is shown in Figure 4. The diagram was created by Biblioshiny software using the data described in the methodology section. The figure shows six groups of affiliations that have collaborations. However, collaborations in research on the topic mainly stem from groups of authors working in 2 or 3 affiliations.

Contribution by Journals
When analyzing this content, the authors eliminated the number of Conference Paper documents to focus on Articles (107 publications). Table 3 describes the quality of the 10 journals with the highest number of articles related to STEM education in ASEAN.
These journals are sorted by quality in Scopus categories: Q2 (4), Q3 (3), Q4 (2), Not Classified (1). It was discovered that there are 3 journals from Turkey and 2 journals from The United States. There is only 1 journal from ASEAN (Journal Pendidikan IPA Indonesia). "Eurasia Journal of Mathematics Science and Technology Education" and "Journal Pendidikan IPA Indonesia" are the journals which are most used by authors, each with 8 articles.  Table 4 discloses crucial data concerning important information regarding the 10 authors with the highest number of published works related to STEM education in ASEAN and Figure 5 shows the number of annual publications of such authors.   Collaboration among author groups is shown in Figure 6. The diagram was created with Biblioshiny software using the data described in the methodology section.

Contribution by Authors
There are 9 groups of authors who collaborate on the topic, of which 4 research groups have the most publications. These have Osman Kamisah, Halim Lilia Bt, Wongwatkit Charoenchai (Mae Fah Luang University, Thailand) and Ibrahim Nor Hasniza (Universiti Teknologi Malaysia) as group research leaders. This diagram also shows the research collaboration between the two groups led by research group leaders from the University Kebangsaan Malaysia, Osman Kamisah and Halim Lilia Bt. Figure 7 describes the keyword network analyzed by the VOSViewer software. The type of analysis is Cooccurrence analysis: The relatedness of items is determined based on the number of documents in which they occur together. The minimum number of documents of a keyword is 3.

DISCUSSIONS Scientific Results of STEM Education in the ASEAN Region have Made Great Progress in the Last Three Years, but Development is Uneven among Countries in the Region
The first research on STEM education in ASEAN started in 2007, although the scientific output in the field of STEM education in ASEAN has only dramatically increased in the last three years (2017-2019). The research that began in 2007, a research on methods to identify variables for predicting STEM enrollment, has the highest number of citations in the field (50 citations) (Nicholls et al., 2007). However, this field received little focus in the following years. Therefore, in the period of 2011-2016, the number of publications relatively plateaued. Scientific output in STEM education has only dramatically increased in the last three years (2017-2019) when the number of publications soared and accounted for 67.43% of the collection. (see Figure 1).
The trend of growth is uneven among countries in the region (see Figure 2). Only 7 out of 11 countries in the region have their journals indexed by Scopus in STEM education and there are four countries with the largest number of publications: Malaysia, Indonesia, Thailand and the Philippines. Malaysia is the leading country, in ASEAN, in terms of scientific output (47.42%), number of leading training institutions (58.33%) and number of leading authors (53.85%). This can be explained by early interest in STEM education from the Government as well as from the Ministry of Education of Malaysia. The term "STEM" was first mentioned by the Malaysian Ministry of Education in the Malaysian education plan (2013)(2014)(2015)(2016)(2017)(2018)(2019)(2020)(2021)(2022)(2023)(2024)(2025). Shortly afterwards, curriculum at all levels were required to include STEM education as a core element in program development and implementation, emphasizing an intensive approach to teaching and learning based on higher-order thinking skills (HOTS), focusing on demand-based learning, problem solving, contextual learning, cooperation learning, and projectbased learning, all in line with STEM's approach (Bahrum et al., 2017).

The Issue of Intra-ASEAN Cooperation on this Topic is not Really Clear and Effective
The analysis of cooperation among ASEAN nations demonstrate that scholars in the region have cooperated with 19 other partner countries, but the contribution of non-ASEAN partner countries is not large (21.74%). The intra-ASEAN cooperation on this topic is not really clear and effective with results mainly coming from the cooperation of authors from Indonesia, Malaysia, and Thailand (see Figure 3). This also shows the influence of cooperation methods including personnel exchange, information exchange, and institutional change that ASEAN is mainly focused on. Other unused and sporadic methods of cooperation are also carried out separately by ASEAN countries.
When analyzing the contribution of research institutions, it was determined that most researches were conducted by a few strong organizations as 38.44% of the articles came from the top 10 organizations with the highest number of publications in this field (see Table 2). 7 out of 12 training institutions come from Malaysia, 3 institutions from Thailand, and 2 institutions from Singapore. It can be seen that all three countries are in the top 4 countries with the highest number of articles. The country ranked third with regard to scientific output under the same topic as Indonesia has no representative on this list. Researches from Thailand come from training institutions: KKU, KMUTNB and KMUTT; Singapore focuses on NTU and NIE; Malaysia has a more even distribution deserving of its leading position in STEM education research. Indonesia has the third largest contribution in this field in the region, but researches do not focus on one or several certain training institutions and thus it has a more even distribution compared to other countries. By analyzing the data collected, the authors discovered that there was cooperation among training institutions in STEM education research, but this cooperation was conducted by certain groups of training institutions, and mainly between 2 or 3 main training institutions.
In consideration of author contribution, among the top 10 authors with the most articles in this field 6 authors are from Malaysia, 2 authors from Thailand, and 2 authors are from Singapore (see Table 3). Among them, 7 authors have citations recorded in the Scopus database system more than 100 times, including 4 authors with citations of more than 400. The two authors who have the most publications in this field are Osman Kamisah and Halim Lilia Bt, both from University Kebangsaan Malaysia, with continuous STEM education research and publishing from 2014 to present. Of the remainder, most have had publications in the last 3 years (see Table  4). This also clearly shows the generally increasing trend of the number of publications in the past 3 years. Cooperation by author group is not plentiful as there are few research groups in the region and there is little connection between groups. (see Figure 6).

Researches on STEM Education in the Region Mainly Focus on Students; the Main Research Fields are Computer Science and Engineering
When considering the network of keywords analyzed by the VOSViewer software (see Figure 7) and words cloud based on keywords of the published publications on STEM of ASEAN countries (see Figure 8), it can be seen that the main fields with the presence of STEM education research are Computer Science: 59 (33.70%) and Engineering: 44 (25.10%). Besides these, we can see that the topics and subjects of research are very diverse. The research subjects mainly focus on students (42); with a much lower number for High School Students (8); while the remaining subjects have hardly any research. The most fundamental and thorough topics focus on Engineering Education; Education Computing. The researches mainly use Surveys (one of the top keywords); keyword analysis also shows that researches focus on teachers' teaching process rather than students' learning process.
While removing the Conference papers it was found that authors sent papers to post in Open Access journal: 41 (38.32%); Other: 66 (61.68%). In terms of analyzing trends, an increase in the rate of articles published in Open Access journals was noted. The top 10 journals published 42.06% of the articles in the collection. ASEAN scholars tend not to submit their works to high-ranking journals: in the top 10 there are no Q1 journals, only 4 Q2 journals with 15 publications (14.02% of the collection).
In addition, there are journals recently indexed by Scopus that have not yet been rated by Scimago (Universal Journal of Educational Research) (See Figure  3). These findings show that ASEAN scholars need to improve the quality of their work to meet the standards of high-ranking journals in the field of STEM education.

CONCLUSION
This paper investigated the academic trend in STEM education literature by means of analyzing the Scopus database, and depicted some characteristics of STEM education literature by using bibliometric and cocitation methods. This paper proposed several findings as followings: (1)

LIMITATIONS
There are some limitations in this study. Firstly, the single use of the Scopus database may not include all scientific articles on STEM Education in ASEAN countries. Using additional bibliographic sources, such as Web of Science and Dimension, will reduce shortcomings in analysis. Secondly, the two most popular and effective bibliographic analysis tools have been used for analysis (Biblioshiny and VOSviewer), but there are some functional limitations that are not possible to overcome at this time, such as statistics of scholars by gender or statistics of new scholars by year. Thirdly, names of authors and their organizations are not standardized in the Scopus database. An author may have several names in different orders, and manual adjustments are not possible. Because the quality of the results are dependent on the quality of input data extracted from the Scopus database, this is the main source of errors in the analysis.