Abstract
The practice of review writing is an essential component of postgraduate students’ academic studies for graduation requirement and especially for those who are undergoing their postgraduate studies by theses by publication. However, very few studies have focused on review genres. In this review, the researchers would like to offer an overview of different types of review articles and identify the trend in the development of the review article genre. The researchers of this study employed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. They identified the published articles specific to the review genres via a structured keyword search in Web of Science, Scopus, and Google Scholar (from the years 2019–2022). A mixed analysis approach (e.g., qualitative analysis combined with quantitative analysis) was conducted to further examine the selected articles using the data visualization software CiteSpace. The results showcased that there were currently a limited number of review types in social science disciplines. The researchers call for more effort to discover new models for writing review genres in the EFL/ESL context. This study also discusses the theoretical and practical implications.
1. Introduction
Writing review articles plays a significant role in students’ postgraduate study. Students are required to write a literature review as part of their degree theses/dissertations, journal articles, theory-based studies, or experimental-based studies [1, 2]. Furthermore, mastering the practical approach to writing a critical literature review is significant for a scholar’s academic success or professional career [3]. Writing good review articles could demonstrate a person’s ability to summarize and synthesize previously published research focusing on a specific topic. It could help both showcase a good command of grasping accessible information for a particular field and assist learning procedures [4]. Despite the importance of good academic writing skills in reviewing articles, most students are not quite sure of the many genres of review articles in academe, and academic writing courses focusing on teaching review articles are neglected in most higher education institutions’ curriculum design [2].
However, review articles (e.g., literature review, critical review, systematic review, and scope review) are significant for postgraduate students’ English academic writing practice in their academic studies [1]. They must write review genres in their degree dissertation/theses or write review articles as the assessment tasks to show their comprehension of the literature they read [2]. Review articles are also popularly welcomed by different journals in science and social science fields [5]. Accordingly, this study will thoroughly analyze review articles based on a mixed research synthesis methodology.
Therefore, this study has two main objectives:(1)To map existing review article research published from 2019 to 2022(2)To explore the trends in the writing of review genres
2. Research Methodology
The researchers used a mixed research synthesis and visual analytic techniques to achieve the two objectives of the study. This review article used a Scopus-based bibliometric analysis and an SLR combined with a scientometric analysis using data visualization software CiteSpace (details in Figure 1).
In particular, setting a timeframe is essential to conducting a literature review [6]. First, there is no time limit for the publication date when conducting Scopus-based bibliometric analysis so that the researchers can showcase a holistic picture of the development of the specific review articles. Second, we selected 2019–2022 as the timeframe when conducting SLR and scientometric analysis so that we can identify the published articles using CiteSpace to map and explore trends by country, institution, and keyword, to visually analyze the “review genres” in different disciplines, and to draw the science map for the last four years (2019–2022). We believe that such a mixed research synthesis can provide a systematic account to complement existing studies and also contribute to review genre studies by achieving the study’s two objectives.
3. A Typology of the Types of Review Articles
From the review of past and current literature, the researchers have identified 14 types of review articles [7] that have been written by scholars and postgraduate students from different disciplines. These 14 types of review articles [7] include (1) rapid review (see [8–11]); (2) scoping review (see [7, 12]); (3) state-of-the-art review (see [7, 13]); (4) systematic review (see [7, 14, 15]); (5) systematic search and review (see [7,16]); (6) systematized review (see [7, 17]); (7) umbrella review (see [7, 18]); (8) critical review (see [7, 19]); (9) literature review (see [7, 20]); (10) mapping review/systematic map (see [7, 21, 22]); (11) meta-analysis (see [7, 23–25]); (12) mixed studies review/mixed-methods review (see [7, 26]); (13) overview (see [7, 27]); and (14) qualitative systematic review/qualitative evidence synthesis (see [7, 28, 29]). In the next subsections, the researchers will explain the type and trend of each of these review articles.
3.1. Rapid Review
Rapid review (RR) refers to a form of knowledge synthesis, which shortens the time duration of reviewing, streamlining, or omitting numerous approaches to produce evidence for stakeholders in a high-efficiency manner [9]. In other words, RRs aim to shorten the time to get a general idea of the currently existing literature of a specific field without an extensive time investment. Initially, RRs are used for policymakers to make evidence-based decisions quickly. Thus, RRs are now gaining legitimacy in the form of rapid evidence assessments [7]. For instance, in the year 2015, the Cochrane Rapid Reviews Methods Group was established and made contributions to develop standards for the reporting of RRs [10]. Recently, Cochrane’s Content Strategy identified the need to explore and the appropriateness of conducting RRs [8].
Generally, RRs are regarded as efficient tools using systematic review approaches to search and critically appraise existing literature for policymaking [11]. Consequently, RRs are now popularly used by policymakers in their daily decision-making. In particular, RRs are used by health agencies worldwide to inform guideline recommendations in urgent and emergent public health contexts [8]. Subsequently, the RR approaches identify some legitimate techniques, possibly utilized to shorten the time duration, for example, focusing on specific questions, using broader search strategies, performing a review of reviews, reducing the number of gray literature studies, and extracting only keywords [7]. However, shortening the timescale might cause publication bias, and insufficient attention to synthesis might cause quality problems and the risk of bias. Furthermore, RRs exist with pros and cons as an efficient tool for decision-making toward urgent issues such as the emergent pandemic of coronavirus disease 2019 (COVID-19) in health settings (for some strong recent examples of medicine-related rapid review (RR), see [30, 31]).
To see the holistic picture of the trend of the RR, the researchers searched Scopus [32], the most frequently used database, using the keyword “rapid review” from numerous disciplines. There is no time limit for the publication date so that the researchers can showcase a holistic picture of the development of the review articles. The result was 1,631 documents. The researchers conducted this search in December 2021.
Figure 2 shows that “rapid review” is mainly used in the medical discipline, occupying 53.6% of the publications. In contrast, there are only 8.4% of the publications from the social science disciplines. So, the publication of RR is scarce in social science disciplines.
From Figure 3, it could be identified that the number of publications of rapid review is increasing. So, this type of genre has its potential for author selection when trying for manuscript publication, specifically for postgraduate students, as those cohorts of students are required to publish their papers to demonstrate their academic understanding and make scholarly contributions in their disciplines.
3.2. Scoping Review
Scoping review (SR) provides a preliminary assessment of the potential size and the scope of accessible research literature. SR is a new method of evidence synthesis and is different from systematic reviews in terms of purposes and aims, wherein SR aims to provide an overview of the accessible research evidence without producing answers to research questions. Hence, SR aims to identify knowledge gaps, set research agendas, and give suggestions for decision-making [7]. Furthermore, SRs could identify in-depth implications for policymakers, as sharing natures of being systematic, transparent, and replicable [12]. However, SRs are still currently being developed. Hence, SRs do not have a procedure for assessing the quality [7]. So, there are precarious existences of SR studies’ findings to be adopted for policymaking (for some strong recent examples of medicine-related scoping review (SR), see [31, 33]).
To see the holistic picture of the trend of the “Scoping review,” the researchers searched Scopus’ most frequently used database using the keyword “Scoping review” from numerous disciplines. There was no time limit for the publication date so that the researchers could showcase a holistic picture of the development of the “Scoping review” articles. As of December 2021, the result from the search was 13,460 documents.
Figure 4 shows that “Scoping reviews” are mainly used in the medical discipline, occupying 43.9% of the publications. Only 11.2% of the publications are from social science disciplines. So, the publication of “Scoping review” is scarce in social science disciplines.
From Figure 5, it could be identified that the number of publications of “Scoping review” is increasing. So, this type of genre has its potential for author selection when trying for manuscript publication, specifically for postgraduate students, as those cohorts of students are required to publish their papers to demonstrate their academic understanding and make scholarly contributions in their disciplines.
3.3. State-of-the-Art Review
A state-of-the-art review focuses more on current research in a particular field or concerning a specific topic [13]. Usually, this review approach identifies current and emerging trends in educational disciplines, research priorities, and standardizations in a specific topic. Thus, this approach could assist researchers by providing new perspectives on a particular field or shedding light for future research [7]. Furthermore, state-of-the-art reviews could help novice researchers in a specific field or those who are dedicated to investigating potentials for the current research. More importantly, publishers in different disciplines have popularly welcomed state-of-the-art reviews, for example, medicines (e.g., the Annual Review of Neurology and Cardiology) and Library and Information Science (e.g., the Annual Review of Information Science and Technology). However, limitations of the state-of-the-art review are common to any “cross-sectional” approach of surveying a field. These approaches are time-bound and might distort the holistic picture of the development of the given topic (for some strong recent examples of medicine-related state-of-the-art review, see [34, 35]).
To see the holistic picture of the trend of the “state-of-the-art review,” the researchers searched Scopus’ most frequently used database using the keyword “state-of-the-art review” from numerous disciplines. There was no time limit for the publication date so that the researchers could showcase a holistic picture of the development of the “state-of-the-art review” articles. As of December 2021, the result of the search was 5,954 documents.
From Figure 6, it could be found that “state-of-the-art review” is mainly used in the engineering discipline, occupying 25.0% of the publications. At the same time, there were only 4.5% of the publications from the social science disciplines. So, the publication of “state-of-the-art review” is scarce in social science disciplines.
From Figure 7, it could be identified that the number of publications of “state-of-the-art review” is increasing. So, this type of genre has its potential when trying for manuscript publication, specifically for postgraduate students, as those cohorts of students are required to publish their papers to demonstrate their academic understanding and make academic contributions in their disciplines.
3.4. Systematic Review
The Cochrane Collaboration defines a systematic review (SR) as a comprehensive high-level summary of primary research on given research questions aiming to identify, select, synthesize, and appraise all high-quality evidence pertinent to the shared research questions [14]. SRs are transparent in the aspects of reporting their approaches to assist other researchers in replicating the procedures [7]. Additionally, an SR identifies and minimizes bias due to the nature of its method being transparent, explicit, and systematic [15]. When conducting an SR, researchers adhere to the guidelines on the handbook supported by the Cochrane Collaboration or the NHS Centre for reviewers [7]. Subsequently, SRs help draw together all existing knowledge on a specific topic. Since the establishment of Campbell Collaboration and the Cochrane Qualitative Methods Group, the inclusion of systematic review has now been extended to a wider range of study designs, including quantitative, qualitative, and mixed-method approaches (for some strong recent examples of medicine-related systematic review (SR), see [36, 37]).
To see the holistic picture of the status quo and identify the trend of the “systematic review,” the researchers searched Scopus’ most frequently used database using the keyword “systematic review” from numerous disciplines. There was no time limit for the publication date so that the researchers could showcase a holistic picture of the development of the “systematic review” articles. As of December 2021, the search result was 369,890 documents.
From Figure 8, it could be found that “systematic reviews” are mainly used in the medical discipline, occupying 56.5% of the publications. In contrast, there were only 3.2% of the publications from the social science disciplines. So, the publication of RR is scarce in social science disciplines.
From Figure 9, it could be identified that the number of publications of “systematic review” is increasing. This type of genre has its potential for author selection when trying for manuscript publication, specifically for postgraduate students, as those cohorts of students are required to publish their papers to demonstrate their academic understanding and make scholarly contributions in their disciplines.
3.5. Systematic Search and Review
Systematic search and reviews incorporate the strengths of critical reviews with a comprehensive, systematic, and effective search process. In particular, this review form informs broad research questions and gives evidence-based suggestions [7, 16]. Additionally, the broad scope of this form of review usually utilizes multiple types of studies, not only using a single approach. In this regard, this approach can provide a comprehensive picture with a broader scope on a specific topic as compared to that of a systematic review, which is restricted to randomized controlled trials [7]. However, the initial search process should meet the preset criteria of a systematic review. The sequential critical review might cause some limitations resulting from the influences of the traditional review approach. Hence, the results of systematic search and reviews might be subjective due to the selection procedures lacking explicit inclusion and exclusion criteria (for some strong recent examples of medicine-related systematic search and reviews, see [38, 39]).
To see the holistic picture of the trend of the “Systematic Search and Reviews,” the researchers searched Scopus’ most frequently used database using the keyword “Systematic Search and Reviews” from numerous disciplines. There was no time limit for the publication date so that the researchers could showcase a holistic picture of the development of the “Systematic Search and Reviews” articles. As of December 2021, the search result was 174 documents.
From Figure 10, it could be found that “Systematic Search and Reviews” are mainly used in the medicine discipline, occupying 42.9% of the publications. In contrast, there were only 8.0% of the publications from the social science disciplines. So, the publication of RR is scarce in social science disciplines. Consequently, there is a wide gap needed to be filled in. Therefore, this research will try to give some implications of writing “Systematic Search and Reviews” in the field of social sciences.
From Figure 11, it could be identified that the number of publications of “Systematic Search and Reviews” is increasing. This type of genre has its potential for author selection when trying for manuscript publication, specifically for postgraduate students, as those cohorts of students are required to publish their papers to demonstrate their academic understanding and make academic contributions in their disciplines.
3.6. Systematized Review
Systematized reviews incorporate one or more strategies of the systematic review process, but systematized reviews differ from systematic reviews. Thus, systematized reviews are performed as postgraduate students’ assignments due to their insufficiency in all resources being accessible [7]. In particular, a researcher can conduct a systematized review individually, possibly using one or more databases, and the researchers might code and analyze all accessible results systematically. Hence, the resulting output “models” the systematic review procedure and requires the researchers to demonstrate an awareness of the entire process and technical proficiency in each step [7]. In this regard, this approach could help build the evidence basis for a more extensive piece of work, for example, a dissertation or a funded research project [17]. However, this approach has some bias caused by its approach not adhering more strictly to guidelines on the implementation of conducting systematic reviews [7] (for some strong recent examples of medicine-related systematized reviews, see [17, 40]).
To see the holistic picture of the trend of the “Systematized reviews,” the researchers searched Scopus’ most frequently used database using the keyword “Systematized reviews” from numerous disciplines. There was no time limit for the publication date so that the researchers can showcase a holistic picture of the development of the “Systematized reviews” articles. As of December, the search result was 197 documents.
Figure 12 shows that “Systematized reviews” are mainly used in the medicine discipline, occupying 33.5% of the publications. In contrast, there were only 18.0% of the publications from the social science disciplines. So, the publication of “Systematized reviews” is scarce in social science disciplines.
From Figure 13, it could be identified that the number of publications of “Systematized reviews” is increasing. So, this type of genre has its potential for author selection when trying for manuscript publication, specifically for postgraduate students, as those cohorts of students are required to publish their papers to demonstrate their academic understanding and make scholarly contributions in their disciplines.
3.7. Umbrella Review
An umbrella review is a form of review summarizing systematic reviews or meta-analyses. Generally, this kind of review is regarded as an overview of reviews, review of reviews, summary of systematic reviews, or synthesis of reviews, sharing the highest level of evidence accessible in medicine [18]. In detail, the emergence of umbrella review was initially due to the consequence of the activities held by the Cochrane Collaboration. Hence, umbrella reviews are derived from systematic reviews, further aggregating findings from other reviews, which inform research questions. In particular, this review form is “compiling evidence from multiple Cochrane reviews into one available document” [7]. However, an umbrella review is a logistic review, so it might not be feasible for other fields such as that of the library and information practice (for some strong recent examples of medicine-related umbrella reviews, see [41, 42]).
To see the holistic picture of the trend of the “umbrella reviews,” the researchers searched Scopus’ most frequently used database using the keyword “umbrella reviews” from numerous disciplines. There was no time limit for the publication date so that the researchers could showcase a holistic picture of the development of the “umbrella reviews” articles. As of December 2021, the search result was 866 documents.
From Figure 14, it could be found that “umbrella reviews” are mainly used in the medicine discipline, occupying 47.9% of the publications. In contrast, there were only 3.1% of the publications from the social science disciplines. So, the publication of “umbrella reviews” is scarce in social science disciplines.
From Figure 15, it could be identified that the number of publications of “umbrella reviews” is increasing. So, this type of genre has its potential for author selection when trying for manuscript publication, specifically for postgraduate students, as those cohorts of students are required to publish their papers to demonstrate their academic understanding and make academic contributions in their disciplines.
3.8. Critical Review
Critical reviews aim to showcase the writers’ essential ideas toward current research and evaluate their quality. Thus, it goes beyond the surface of simple descriptions of identified articles and generates vital analysis and conceptual innovations [7, 19]. Hence, effective critical reviews present, analyze, and synthesize accessible material from numerous sources. Consequently, its resultant model might consist of a synthesis of existing models or schools of critical thought or a totally new interpretation of the current data [7, 19]. Subsequently, critical reviews are supposed to be objective for assessing the strengths and weaknesses of the existing literature. Furthermore, critical reviews provide opportunities to “take stock” and critically evaluate a specific field's current body of work. Additionally, it might attempt to solve critical issues. Therefore, it could assist in proposing a “launch pad” for new stages of conceptual development and sequential “testing” [7](for some strong recent examples of medicine-related critical reviews, see [43, 44]).
To see the holistic picture of the trend of the “Critical reviews,” the researchers searched Scopus’ most frequently used database using the keyword “Critical reviews” from numerous disciplines. There was no time limit for the publication date so that the researchers could showcase a holistic picture of the development of the “Critical reviews” articles. As of December 2021, the search result was 43,409 documents.
From Figure 16, it could be found that “Critical reviews” are mainly used in the medicine discipline, occupying 20.2% of the publications. In contrast, there were only 9.7% of the publications from the social science disciplines. So, the publication of “Critical reviews” is scarce in social science disciplines.
From Figure 17, it could be identified that the number of publications of “Critical reviews” is increasing. So, this type of genre has its potential for author selection when trying for manuscript publication, specifically for postgraduate students, as those cohorts of students are required to publish their papers to demonstrate their academic understanding and make academic contributions in their disciplines.
3.9. Literature Review
Literature reviews (LRs) refer to searching or evaluating the accessible literature in a specific topic or selected field. Furthermore, LRs document the pertinent data for a chosen subject or topic being focused on. Hence, LRs demonstrate the researchers’ in-depth and comprehensive knowledge of the selected topic. So, researchers can identify research gaps, make decisions about the method to fit into the gaps, and contribute to the existing body of the current work [20]. Generally, LRs cover a broad range of subject matter at different levels of completeness and comprehensiveness based on critical analyses of existing literature [7]. However, LRs review previously published literature. This is where the selected articles share some degree of quality or have gone through the peer-review process.
Additionally, LRs include some procedures for identifying materials and justifying the quality of the materials using preset criteria for critical analysis following their contributions or values [7]. In particular, LRs seek to identify research gaps, establish a new framework based on previous work, summarize what has been achieved, and ensure unique contributions [7] (for some strong recent examples of medicine-related literature reviews (LRs), see [45, 46]). However, LRs lack explicit instructions to broaden scope or critically analyze collected data [20]. Consequently, researchers might be subjective to select articles based on their own perspectives, which might cause bias.
To see the holistic picture of the status quo and identify the trend of the “literature review,” the researchers searched Scopus’ most frequently used database using the keyword “literature review” from numerous disciplines. There was no time limit for the publication date so that the researchers could showcase a holistic picture of the development of the “literature review” articles. As of December 2021, the search result was 236,896 documents.
From Figure 18, it could be found that “literature reviews” are mainly used in the medicine discipline, occupying 30.0% of the publications, while there was only 9.6% of the publications from the social science disciplines. So, the publication of “literature review” is scarce in social science disciplines.
From Figure 19, it could be identified that the number of publications of “literature review” is increasing. So, this type of genre has its potential for author selection when trying for manuscript publication, specifically for postgraduate students, as those cohorts of students are required to publish their papers to demonstrate their academic understanding and make academic contributions in their disciplines.
3.10. Mapping Review/Systematic Map
Mapping reviews/systematic maps are designed to present a comprehensive picture of the status quo of a specific field via classification and counting contributions related to the categories, using a visual synthesis of the data [21]. This type of approach is question-based. Grant and Booth [7] report that mapping review/systematic map aims to categorize, characterize patterns, and identify trends or themes in evidence-based production or publication. Generally, mapping reviews/systematic maps enhance the contextualization of in-depth systematic literature reviews into a broader literature range and identify gaps in the evidence-based approach. In this sense, they are regarded as an effective tool for providing explicit and visualized data for policymakers, researchers, and stakeholders to answer research questions [7, 22]. However, mapping review/systematic maps are time-constrained, lack critical synthesis, and analyze more in-depth methods. Thus, mapping reviews/systematic maps do not generally perform the quality assessment, whereas this type of approach characterizes studies in accordance with the design of the study.
To see the holistic picture of the status quo and identify the trend of the “Mapping Review,” the researchers searched Scopus’ most frequently used database using the keyword “literature review” from numerous disciplines. There was no time limit for the publication date so that the researchers can showcase a holistic picture of the development of the “Mapping Review” articles. As of December 2021, the search result was 411 documents.
From Figure 20, it could be found that “Mapping Review” is mainly used in the medicine discipline (for some strong recent examples of medicine-related mapping reviews, see [47, 48]), occupying 26.1% of the publications, while there was only 12.8% of the publications from social science disciplines. So, the publication of “Mapping Review” is scarce in the social science disciplines.
From Figure 21, it could be identified that the number of publications of “Mapping Review” is increasing. So, this type of genre has its potential for author selection when trying for manuscript publication, specifically for postgraduate students, as those cohorts of students are required to publish their papers to demonstrate their academic understanding and make academic contributions in their disciplines.
To present a holistic picture of the status quo and identify the trend of the “Systematic Map,” the researchers searched Scopus’ most frequently used database using the keyword “Systematic Map” from numerous disciplines. There was no time limit for the publication date so that the researchers could showcase a holistic picture of the development of the “Systematic Map” articles. As of December 2021, the search result was 407 documents.
Figure 22 shows that “Mapping Review” is mainly used in environmental science, occupying 35.2% of the publications, while there was only 7.9% of the publications from social science disciplines. So, the publication of “Systematic Map” is scarce in social science disciplines.
From Figure 23, it could be identified that the number of publications of “Systematic Map” is increasing. So, this type of genre has its potential for author selection when trying for manuscript publication, specifically for postgraduate students, as those cohorts of students are required to publish their papers to demonstrate their academic understanding and make academic contributions in their disciplines (for some strong recent examples of medicine-related systematic map articles, see [49, 50]).
3.11. Meta-Analysis
Generally, meta-analysis is a form of statistical analysis of data from independent primary studies focusing on the same question, aiming to generate a quantitative evaluation of the studied field [51]. In other words, meta-analysis is an effective technique that statistically combines the results of previous research to present a more precise effect of the results [7]. In particular, meta-analysis is based on randomized, controlled clinical trials. Generally, a high-quality systematic review is essential to a meta-analysis of the literature. This is because a meta-analysis must include all accessible studies to ensure validity. This approach contains criteria such as the population being identified, the intervention being studied, and the investigated comparison. Hence, this approach is required to ensure that the same assessment or results are being measured using the same method. Also, these processes are guaranteed to be conducted at the same time intervals [7, 23]. The relationship among meta-analysis, systematic reviews, and review is clearly shown in Figure 24.
As posited by Shelby and Vaske [25], there are two significant advantages of meta-analysis: practical significance and rigorous methodology. The first advantage resides in this approach encouraging researchers to concern all the accessible literature and give evidence to repeated results using a summarized statistic. Hence, a meta-analysis could assist researchers in finding effects or relationships that are obscured in other approaches [25]. The second advantage is that meta-analysis provides a rigorous methodology for quantitative research synthesis. Hence, adopting a particular method encourages researchers to be more familiar with the data, generate focused research hypotheses, and identify moderator variables [24]. Therefore, meta-analysis is an effective quantitative tool for evaluating the meaning of the existing literature. However, critics of a meta-analysis argue against it due to the inappropriateness of combining studies not totally similar [25]. Furthermore, following careful documentation procedures can help mitigate such problems.
To see the holistic picture of the status quo and identify the trend of the “Meta-analysis,” the researchers searched Scopus’ most frequently used database using the keyword “Meta-analysis” from numerous disciplines. There was no time limit for the publication date so that the researchers could showcase a holistic picture of the development of the “Meta-analysis” articles. As of December 2021, the search result was 336,631 documents.
Figure 25 shows that “Meta-analysis” is mainly used in the medicine discipline (for some strong recent examples of medicine-related meta-analysis, see [52, 53]), occupying 55.5% of the publications, while there was only 2.5% of the publications from the social science disciplines. So, the publication of “Meta-analysis” is scarce in social science disciplines.
From Figure 26, it could be identified that the number of publications of “Meta-analysis” is increasing. So, this type of genre has its potential for author selection when trying for manuscript publication, specifically for postgraduate students, as those cohorts of students are required to publish their papers to demonstrate their academic understanding and make academic contributions in their disciplines.
3.12. Mixed Studies Review/Mixed-Methods Review
As Sandelowski et al. [26] defined, the mixed studies review/mixed-methods review could help enlarge the conceptualization of evidence, be methodologically inclusive in nature, synthesize all accessible evidence, and be useful for a broader range of consumers [26]. In other words, this approach can refer to any combination of approaches, in which at least one of the elements is a literature (usually systematic) review [7]. Mixed studies review/mixed-methods reviews could assist policymakers by presenting a more comprehensive understanding of a specific intervention or condition that is valid [7]. This approach could help present a potentially more holistic picture of the research landscape in a particular topic field compared with single-method reviews. However, researchers might meet the challenges of appraising and synthesizing both quantitative research and qualitative research, with the additional challenges of combining the resultant products [7].
To see the holistic picture of the status quo and identify the trend of the “Mixed Studies Review,” the researchers searched Scopus’ most frequently used database using the keyword “Mixed Studies Review” from numerous disciplines. There was no time limit for the publication date so that the researchers could showcase a holistic picture of the development of the “Mixed Studies Review” articles. As of December 2021, the search result was 151 documents.
From Figure 27, it could be found that “Mixed Studies Review” is mainly used in the medicine discipline (for some strong recent examples of medicine-related mixed studies review, see [54, 55]), occupying 40.7% of the publications, while there was only 17.8% of the publications from the social science disciplines. So, the publication of “Mixed Studies Review” is scarce in social science disciplines.
From Figure 28, it could be identified that the number of publications of “Mixed Studies Review” is increasing. So, this type of genre has its potential for author selection when trying for manuscript publication, specifically for postgraduate students, as those cohorts of students are required to publish their papers to demonstrate their academic understanding and make academic contributions in their disciplines.
3.13. Overview
In medical disciplines, an overview is a generic term used for many forms of summaries of the medical literature [27]. Thus, this approach aims to survey the literature and describe its features. In this sense, it could be applied for diverse types of literature review, with different degrees of systematicity [7]. Initially, the term “overview” was regarded as synonymous with “systematic review” to express that specific method [27]. Consequently, there are some debates toward the value of the term “overview,” while the term still has its attractiveness to readers [7]. Interestingly, overviews can provide a broader range of literature and a vast landscape of the selected topic area. Additionally, overview plays a meaningful role for novices to a new field [27]. However, the term “overview” is utilized as a non-discriminant term for reviews of changing rigor and quality [7]. In this regard, the Cochrane Collaboration took measures to distinguish “systematic overview,” employed synonymously for “systematic review,” from other forms of overview that typically lack systematic approaches and detailed reporting [7] (for some strong recent examples of medicine-related overview, see [56, 57]).
To see the holistic picture of the trend of the “overview,” the researchers searched Scopus’ most frequently used database using the keyword “overview” from numerous disciplines. There was no time limit for the publication date so that the researchers could showcase a holistic picture of the development of the “overview” articles. As of December 2021, the search result was 631,110 documents.
Figure 29 shows that “overview” is mainly used in other disciplines, occupying 28.6% of the publications, while there was only 7.7% of the publications from the social science disciplines. So, the publication of “overview” is scarce in social science disciplines.
From Figure 30, it could be identified that the number of publications of “overview” is increasing. So, this type of genre has its potential for author selection when trying for manuscript publication, specifically for postgraduate students, as those cohorts of students are required to publish their papers to demonstrate their academic understanding and make academic contributions in their disciplines.
3.14. Qualitative Systematic Review/Qualitative Evidence Synthesis
Qualitative systematic review (QSR)/qualitative evidence synthesis (QES) is an umbrella term for the methodologies pertinent to the systematic review of qualitative research evidence. Additionally, this form of approach is a type of a stand-alone review or as a part of a review of complicated interventions, systems, or guideline development [28]. In other words, QSR/QES refers to a form of approach for integrating or comparing the findings from qualitative studies [7]. Furthermore, QSR/QES aims to aggregate the results from qualitative studies to build a comprehensive understanding of the selected issues [28]. Consequently, QSR/QES shares the excellent standard of presenting holistic interpretations associated with the impacts of a situation, intervention, or policy on the lived experiences and feelings of the stakeholders [29]. Subsequently, QSR/QES has numerous strengths in complementing the research evidence with the other two elements of evidence practice (e.g., user-reported and practitioner-observed considerations) [7]. Hence, this type of approach helps to provide generalizable insights and robust findings compared with quantitative methods, rather than simple comments from quantitative questionnaires or surveys [28]. However, there are some debates on QSR/QES, as these are still new. In this sense, the discussions mainly focus on whether the prominent model for QSR/QES is the systematic review approach or whether it is better to adjust and employ terms from original qualitative research (namely, grounded theory, case study, or purposive sampling) [7] (for some strong recent examples of medicine-related qualitative systematic reviews, see [58, 59]).
To see the holistic picture of the status quo and identify the trend of the “Qualitative Systematic Review,” the researchers searched Scopus’ most frequently used database using the keyword “Qualitative Systematic Review” from numerous disciplines. There is no time limit for the publication date so that the researchers could showcase a holistic picture of the development of the “Qualitative Systematic Review” articles. As of December 2021, the search result was 151 documents.
From Figure 31, it could be found that “Qualitative Systematic Review” is mainly used in medicine disciplines, occupying 46.3% of the publications. In comparison, there were only 7.6% of the publications from the social science disciplines. So, the publication of “Qualitative Systematic Review” is scarce in social science disciplines.
From Figure 32, it could be identified that the number of publications of “Qualitative Systematic Review” is increasing. So, this type of genre has its potential for author selection when trying for manuscript publication, specifically for postgraduate students, as those cohorts of students are required to publish their papers to demonstrate their academic understanding and make scholarly contributions in their disciplines.
4. Trend of Review Articles
To give a comprehensive picture of the trend of “Review articles” worldwide, the researchers use a systematic and objective approach to the scientometric analysis of research literature to map the existing articles and identify the trend of the “Review articles,” adopting CiteSpace data visualization software, along with evaluation of the publication years, authors, countries, keywords, abstracts, etc. Thus, a systematic literature review (SLR) was conducted to collect data by selecting 2,811 articles from three online databases, namely, Web of Science, Scopus, and Google Scholar, according to the keywords language, document types, etc., and the time duration was 2019 to 2022. The researchers conducted this SLR in December 2021. As a standard way of conducting an SLR, PRISMA involves four steps: identification, screening, eligibility, and data abstraction and analysis.
4.1. Systematic Literature Review in This Study
4.1.1. Identification
The identification process was performed in December 2021. In this phase, 3,000 articles from Scopus, 2,000 from WoS, and 14,500 from Google Scholar were carefully selected.
4.1.2. Screening
In the screening phase, articles meeting SLR’s requirements were chosen based on eligibility, inclusion, and exclusion criteria (Table 1).
4.1.3. Eligibility
In the third phase, articles were included or excluded in accordance with the preset criteria. 6,480 similar articles were excluded from the database. 2811 articles were selected for review articles based on the review articles and the inclusion and exclusion criteria.
4.1.4. Data Abstraction and Analysis
In the final stage of data abstraction and analysis, we evaluated, reviewed, and analyzed all articles. We selected 2811 articles for this study (Figure 33). Our SLR procedure can be found in Figure 33.
4.2. Scientometric Analysis
In this phase, 2,811 articles from three online databases, Web of Science, Scopus, and Google Scholar, carefully selected by the SLR procedure, were reviewed through a scientometric analysis. This technique was employed to visualize the bibliometric networks to map and explore the trend of the review articles in the recent four years (i.e., 2019–2022). The details are shown in Figure 34.
5. Results and Discussion
5.1. Network Map by Country/Region
Regarding the number of publications by country, the United States produced the most significant number of review articles. Furthermore, these countries have powerful collaborative connections; 180 pooled connections could be found from international collaborations. Therefore, it could be seen that review articles are popularly welcome worldwide. The details are shown in the following Figure 35.
5.2. Network Map of the Keyword Co-Occurrence and Evolution Analysis
Keywords can identify the topic of a research article. Keyword co-occurrence networks can help investigate popular issues in the research field during the selected period. The evolution network can demonstrate the development of the knowledge area during a specific time. Figure 36 shows the keyword co-occurrence network of the research in the “Review articles.” It includes 154 nodes and 180 links. The keyword occurrence frequency identifies the size of the node. The top ten keywords in terms of frequency were human (438), article (422), nonhuman (124), priority journal (88), a systematic review (86), procedure (74), female (67), male (63), animal (45), and adult (44). This finding indicates that most of the review articles were published by researchers from medical disciplines or human resources disciplines. Three keywords received relatively high betweenness centrality scores: “human” (0.48), “nonhuman” (0.38), and “article” (0.36). Keywords with high betweenness centrality reveal popular topics in the human resource disciplines and journalism subjects. The details are shown in Figure 36.
This finding indicates that the most popular research area and citations increased during a specific period. The top nine most strengthened keywords (see Table 2) from 2019 to 2022 were identified, including “pandemic” (burst strength = 1.6412, 2020–2022), “web of science” (burst strength = 0.8675, 2020–2022),“overall survival”(burst strength = 0.8675, 2020–2022), “pandemics” (burst strength = 0.8675, 2020–2022), “non-insulin-dependent diabetes mellitus” (burst strength = 0.771, 2020–2022), “antibiotic agent” (burst strength = 0.6745, 2020–2022),“management” (burst strength = 0.6745, 2020–2022), “anemia” (burst strength = 0.6745, 2020–2022), and “attention” (burst strength = 0.4816, 2020–2022). The findings revealed that the outbreak of COVID-19 increased the number of review articles.
In particular, it was found that review article publications have focused on “pandemic,” “management,” and “health.” In this regard, the essential function of review articles for policymaking, information, and quick-decision toward emergent issues could be seen. The details are shown in Table 2. Additionally, it could also be found that high-quality review articles mainly use the Web of Science database to search the literature. Therefore, this finding confirms the suggestions by Marshall [60], which gave suggestions on using the Web of Science for data collection for writing review articles.
Next, the evolution of research hotspots was identified by the period of keywords through co-occurrence links. Figure 37 shows the keyword evolution in the “review article” studies from 2019 to 2022 worldwide. In 2019, this field witnessed numerous frequently emerging concepts such as “article,” “human,” “nonhuman,” “systematic review,” and “priority review.” In 2020, the keyword “Covid-19” indicated that review articles could reflect society's current issues and help make quick decisions. Most importantly, these findings revealed that review articles are easy to be published in a short time and are highly cited by other articles. In 2022, the keywords “energy” and “greenhouse” indicated that review articles got attention from researchers in energy disciplines and also showed that researchers' attentions have shifted from “Covid-19” to “re-build a better world.” In the recent four years, “review articles” have been increasingly developed in English article publications. The details are shown in Figure 37.
6. Significance of Review Genres
Generally, review articles are the most accessible genre to get published for postgraduate students who are novice researchers. Getting review articles published is also a task for most of the master and PhD students. Moreover, this type of journal article is the highest citation form of journal papers [5,61]. Therefore, review articles are significant for academic study postgraduate students (novice researchers). Furthermore, many reasons indicate the significance of review articles. Firstly, writing review articles can enhance a writer’s knowledge about the specific topic selected. Hence, writing review papers can assist the learning procedures and enrich the understanding of a particular topic. Secondly, literature reviews could “demonstrate a researcher’s knowledge of the specific field. In this regard, it could provide credibility to the author and integrity to the work’s overall argument” [4]. Hence, reviewing and analyzing the published literature can identify the gaps of the extant literature. So, this could help researchers inform the argument for why future research is required [3]. Therefore, review articles play significant roles in the academic research and researchers’ academic career.
Interestingly, further developed by Palmatier et al. [5], it could be found that there are some benefits for conducting review research. Firstly, review articles can help resolve definitional ambiguities and outline the scope of the specific topic. Secondly, review articles could help provide a comprehensive, synthesized overview of the status quo of the extant knowledge. Thirdly, review articles could help identify the gaps in research. Fourthly, review articles could help assess fundamental research approaches and specific findings. Fifthly, review articles could help develop a conceptual framework to integrate and better develop previous research. Finally, review articles could help give suggestions, identify the trend, and shed light for future studies.
7. Conclusion
This study’s research objective was, first, to map review genre research and, second, to identify its trends in different disciplines during the period 2019–2022. To achieve these objectives, we performed a mixed analysis to review selected articles from the domains of research disciplines, annual publication trends, keyword bursts, and co-occurrences of keywords to demonstrate research trends. Analysis of research disciplines showed that review genres are now widely used in a variety of disciplines, while there is still a call for more publications in the review genre for social science disciplines. Notably, analysis of the disciplines also revealed that all types of “Review articles” focus on medical issues, so we have included examples in each section of each type of review genre in medicine discipline to ensure audiences learn more about each type of review genre.
Furthermore, we performed a scientometric-assisted review of 2,811 articles from the three databases (e.g., Web of Science, Scopus, and Google Scholar) using CiteSpace to visualize review genre research trends via keyword burst and keywords’ co-occurrence. Keywords were also utilized to establish the occurrence network to reveal popular topics from 2019 to 2022. Additionally, the time factor was studied to identify keyword evolution, revealing that the three most frequently used keywords were “human,” “article,” and “nonhuman.” In the scientometric analysis, CiteSpace software crystallized review genre-related research’s significant research findings [62]. In this regard, however, we believe that future studies should focus more on teaching instructions on writing review genres [63].
Moreover, all types of research depend on review articles as a foundation [5, 61]. Review genres can provide information for knowledge development, directions for policy and practice, provide evidence of the effect of a given action, and, if well conducted, can produce new ideas and suggestions for the field at large [7]. In this way, they serve as foundations for future research and theory, if we recognize and eliminate actual research gaps rather than constantly doing the same thing [64]. In that case, the researchers can develop better hypotheses and research questions, ultimately improving the quality of research in general [8]. Therefore, conducting qualified review articles could improve researchers’ research quality by focusing on a specific topic to enrich knowledge, mapping the status quo, and identifying the trend [64].
Data Availability
The data supporting the findings of this study are available within the article and its supplementary material. Raw data that support the findings of this study are available from the corresponding author upon reasonable request.
Conflicts of Interest
The authors declare that they have no conflicts of interest.