1 Introduction

Maritime trade and seaports have evolved as an integral part of global economic development, with the trade through sea comprising more than 80 percent of the volume of international merchandise trade [1] and connecting developing countries with developed as well as between various modes of global logistics and transportation [2,3,4,5]. Given the critical role of maritime seaports in the worldwide supply chain, there has been an exponential rise in research in maritime seaport-related studies covering diverse topics and themes. With the burgeoning volumes of publications, as recommended by Moral-Muñoz et al. [6], bibliometric and systematic studies are helpful in scientifically tracking the growth trend of publications and in evaluating the essential characteristics and attributes of the research studies, supported by various contemporary statistical analysis software tools. Junquera et al. [7] highlighted the benefit of bibliometric data analysis in assisting the exploration of different characteristics and attributes related to the study area, such as publication trends, authors in the field, themes of ongoing research along country-specific details which are essential to understanding and enhancing the body of knowledge on the topic of interest, the ongoing trend, and aid in exploring the characteristics associated with different themes related to the subject of study.

Numerous bibliometric and systematic review studies by multiple authors discuss the synthesis of reviews on port management, port governance, port economics, digitization and new-age automation technology adoption in ports, and port choice selection topics. In their novel bibliometric study, Pallis et al. [8] identified significant emerging themes under various categories of port-related research. A large number of bibliometric and systematic review studies were published in the recent decade [9,10,11,12,13,14,15,16,17,18,19,20,21,22] that covered many of the themes and categories, including “green port”, “container port terminal”, “seaport competitiveness”, “port sustainability” “dry port”, “port management”, “digitization of port operations”, “smart port.”

However, a holistic bibliometric data analysis on the “port performance” topic could not be traced in the extant publications. For shipping ports, which act as the backbone of the maritime transportation ecosystem [23, 24], the port’s competitiveness and performance are considered one of the most critical elements [25]. For the growth and sustenance of the global maritime trade, the performance of the ports plays a crucial role. Numerous studies [5, 24,25,26,27] have proven the positive impact of the performance of ports on the economic development of a country and how poorly performing ports result in lower trade volumes, especially in developing or less-developed countries. Given ports' vital role in economic development through boosted production-consumption in the value chain and increasing global trade, along with the interest of academicians, researchers, and policymakers in the field, the literature on port performance has been growing [5]. Bibliometric and systematic analysis can give an overview of the studies on port performance. It can demonstrate a broad understanding of ongoing research work and themes since the first publication will benefit researchers and practitioners in port management.

Therefore, this study aims to explore the bibliometric data of research articles related to the performance of ports and identify the trend and ongoing themes of research through bibliometric data analysis. The study also attempts to analyze scholarly publications' evolution and critical insights on port performance-related fields regarding themes or topics, subject areas, leading journals, citations, and country-wise contributions, along with collaboration and outline future research directions. This novel study explores the bibliometric data on the “port performance” studies published in the Scopus database. It analyzes the data through creative visualizations to identify trends, establish ongoing research themes, and outline future research.

The following sections cover the literature overview on port-related bibliometric studies to trace the ongoing research and identify the gap along with framing research questions, then describe the methodology adopted in the current bibliometric survey, followed by results and discussion, leading to drawing conclusions along with contributions and outlining the implications and future research directions.

2 Review of literature

The literature review of the extant body of knowledge on port-related bibliometric analysis studies identified many significant contributions in the Scopus database. The keywords search using the combination “TITLE-ABS-KEY ("port" OR "seaport" OR "shipping port" OR "maritime port" OR "maritime shipping port" OR "container port" AND bibliometric OR scientometric) AND (LIMIT-TO (LANGUAGE, "English"))” identified 48 articles. After the screening, 25 bibliometric data analyses published since 2010 were shortlisted and reviewed in detail. Among those, eight were published in 2023 and 7 in just the first quarter of 2024, indicating the pace with which research is burgeoning in port-related fields. Elsevier is the leading publisher, with about nine publications covering around 30% of the total publications. Springer and Routledge share the second spot with four publications each. “Maritime Policy and Management” and “Sustainability” were the leading sources, with 4 and 2 bibliometric articles published, respectively. Table 1 summarises the literature reviewed, along with their source and citations.

Table 1 Summary of bibliometric studies articles on port along with source
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The bibliometric studies on port-related topics commenced with the review article of Pallis et al. (2010), who conducted a bibliometric analysis of port economics and management policy-related topics to unravel the emerging research field based on the papers published between 1997 and 2008 in multiple scholarly databases such as ScienceDirect, JSTOR, Google Scholar, and Econlit. They concluded that research on port-related studies is rapidly emerging, international collaboration is rising, and the majority were on container port terminals. We could also identify the recent trend of literature on port-related studies getting focussed on container terminals discussing innovation and digital automation of container terminal operations and the application of new-age big-data technologies, Artificial Intelligence (AI), and Machine learning techniques (ML), and Internet-of-things platforms for productivity improvement and real-time port operations management.

Along the lines of technology development and integration in port management, the study of Li et al. [34] focused on the novel technology integrated ports with the concept of Smart ports incorporating intelligent digital technology and infrastructure comprising of cloud computing technology, big data analytics, Internet of things (IoT), and AI-based applications for capacity and resource optimization as a new-age solution to cope with the challenges faced in the dynamic port industry. The most recent publication on the maritime port sector is the bibliometric analysis study by Diniz et al. [22] on the United Nations’ Sustainable Development Goals (SDG), wherein they used IRaMuTeQ and VOSviewer software tool to evaluate the trends through a systematic literature review. In the years 2023 and 2024 till the 20th of April, published six articles each year, the highest number of bibliometric-related publications since 2010. The highest citation of 177 was received for the study by Davarzani et al. [9] on “green ports,” followed by 122 citations for the study of Pallis et al. [8] on port economics and management.

Many studies [42,43,44,45] have pointed out the dynamic nature of maritime business. Amidst the dynamic nature of the port sector, as highlighted by Mantry and Ghatak [46], the country’s economic development is impacted by poor port performance. As per the United Nations Conference on Trade and Development (UNCTAD) [1, 47], more than 80% of the international trade volume is handled through maritime transportation. [23, 48] Studies have emphasized the significance of ports in the economic growth of a country. Given ports' vital contributions to economic development and global trade, along with the increasing interest of academicians, researchers, and policymakers, the literature on port performance has grown exponentially, especially in the last decade.

OConnor et al. [5] systematically reviewed port performance-related studies to identify performance dimensions and discussed port performance as a multi-dimensional construct. However, the study should have addressed the other characteristics and attributes that cause and impact the performance of ports. Notably, Wang et al. [35] were the first to use the WoS database exclusively for collecting bibliometric data for the period 2000 to 2020 and analyzing the data using the CiteSpace software tool. Their study focused on visual mapping of bibliometric data to uncover insights into trends of publications and authors along with their affiliations and countries and keyword analysis to derive more frequently discussed topics and themes. Though future research directions were indicated in the studies and many themes were highlighted, there needs to be more on the performance of ports and related variables for enhancing port performance. The scientometric analysis and computational text analysis by Sung-Woo et al. [49] were specific to port performance-related bibliometric study; however, they focused mainly on port and shipping along with supply chain logistics-related high-quality publications between 2000 and 2018 in journals listed in the Science Citation Index (SCI), Science Citation Index Expanded (SCIE), and Social Science Citation Index (SSCI) available in the Scopus and the WoS scholarly databases only. Since the number of articles was 1947 in the count, they adopted topic modeling using a text mining technique called “Latent Dirichlet Allocation (LDA)” to uncover significant research topics.

The qualitative study by Somensi et al. [50] analyzed the bibliographical characteristics of evaluating port performance studies published during 2000—2016 and discussed management practices and organizational performance aspects. Bibliographical data comprising 3112 articles for their research was collected from popular scholarly databases, and a series of keywords were used to search for performance, evaluation, and management-specific articles. Bibliographical portfolio selection and analysis were done using the Knowledge Development Process-Constructivist (ProKnow-C) tool developed at the Federal University of Santa Catarina. They selected 37 articles at the end of the portfolio selection procedure to analyze further regarding an author, journal, topic, and country analysis. They suggested increasing the research by extending the analysis period and conducting a more in-depth systematic analysis as the future research direction.

To address the gap identified, bibliometric data analysis can be adopted to explore the hidden characteristics and attributes related to the study area, such as publication trends, authors in the field, themes of ongoing research along with country-specific details and help with deep insights on the continuing trend, and identify the characteristics associated with different themes related to the topic of study. Therefore, a holistic bibliometric data-based exploratory study on “port performance” can give an overview of all the studies on port performance to date and demonstrate a broad understanding of ongoing research work and themes since the first publication. Further, the previous studies have not discussed co-occurrence or co-citation in articles published on port performance.

In this backdrop and taking a cue from shortcomings identified through the literature review, this study focuses on the following research questions:

  • What is the trend and evolution of research publications in maritime port performance?

  • What are the dynamics of journals publishing articles and citations of articles related to port performance?

  • Which countries have given utmost importance to port performance-related studies?

  • How are the citations, authorship, and collaborations shaping up?

  • What are the new and emerging topics and themes related to port performance studies?

3 Methodology

Akbari et al. [51] discuss how bibliometric analysis has recently received greater importance and hailed bibliometric analysis methods over traditional methods due to the benefits associated with conducting bibliometric analysis. The authors adopted an exploratory research approach by analyzing the bibliometric data downloaded from the most popular scholarly database, Scopus, to assess the trend and existing scenario of port performance-related studies, leading to the researcher's analysis and interpretation of visualized data in various plots and diagrams using relevant software tools. Scopus is one of the leading scholarly databases that has witnessed increasing citable articles and multi-disciplinary publications that provide quick and authoritative access to high-quality, comprehensive, and reliable content in multi-disciplinary fields [52,53,54].

In the first phase of the bibliometric study, we started with the search for scholarly articles in the Scopus database using an initial set of keywords and Boolean operator combinations to retrieve the relevant and possible publications available in the Scopus database. After multiple trials, the keyword combination was identified as "port performance" OR "performance of port" OR "performance of the port." With the identified keywords and boolean operators, the search in the Scopus database was conducted using the combination of keywords and Boolean operators as “ALL (("maritime port" OR "sea-port" OR "sea? port" OR "seaport" OR "shipping port" OR "container port" OR "container terminal port") AND ("port performance" OR "performance of port" OR "performance of the port" OR "performance of the shipping port" OR "performance of the maritime port" OR "performance of the seaport" OR "performance of shipping port" OR "performance of seaport")) AND (EXCLUDE (SUBJAREA, "PHAR") OR EXCLUDE (SUBJAREA, "NURS") OR EXCLUDE (SUBJAREA, "VETE") OR EXCLUDE (SUBJAREA, "NEUR") OR EXCLUDE (SUBJAREA, "MEDI") OR EXCLUDE (SUBJAREA, "CHEM") OR EXCLUDE (SUBJAREA, "BIOC") OR EXCLUDE (SUBJAREA, "PHYS")) AND (EXCLUDE (DOCTYPE, "no") OR EXCLUDE (DOCTYPE, "er") OR EXCLUDE (DOCTYPE, "tb") OR EXCLUDE (DOCTYPE, "ed")) AND (LIMIT-TO (LANGUAGE, "English")).” The scope of the study was limited to research, review, book, and conference publication articles available in English. The search was conducted on the 20th of April, 2024.

In the second phase, the filtered documents available after the search were downloaded from the Scopus database in CSV and Bib file formats for further bibliometric data analysis. Scopus database also provides a quick, ready-to-use results analysis option with basic diagrams representing documents per year, by source, by author, affiliation, country, type, and subject area, and by funding agency. These results are also available for download in CSV file format for customized data visualization and extended analysis. This was followed by a distinct analysis of the downloaded datasets in the third phase to analyze and interpret, leading to the discussion and conclusion in the fourth phase. Further, scientometric analysis was performed based on co-authorship and co-occurrence using the VOSviewer software tool [55]. VOSviewer is acknowledged as a scientific tool for data visualization to perform exploratory data analysis on various aspects of publication, such as keywords, countries of research activity, and its density [56]. Bibliometric data related to the subject area, yearly trend, journal, author, citation, and country-wise publication was visualized and analyzed using open-source R and Python software tools and relevant available libraries and packages. “bibliometrix” package available in R was the primary tool used for importing the raw bibliometric data and later developing many visualizations supported with Python for data cleaning before further analysis and developing visualizations.

The evolution themes developing over time were analyzed with three cutting points in 2008, 2014, and 2020, representing an equal distribution from 2008 to April 2024. The first cutting point of 2008 was fixed as the number of publications saw an upswing after 2007 as per the preliminary analysis and hence could be the milestone to start with further analysis as the first cutting point. Following the benchmark values adopted by Cobo et al. [57] and Wang et al. [58] in their bibliometric analysis study, the word count was set to default as 200, minimum cluster frequency of 5 per thousand documents, the number of labels for each cluster as 4 for optimal mapping with minimum weight index as 0.1 and thematic analysis using the Louvain clustering algorithm since past studies [59, 60] have proven the Louvain algorithm’s consistency of performance and better results of modularity when compared with other clustering algorithm approaches. Informative trends and patterns identified through the analysis were discussed, and conclusions were outlined, leading to future research directions and highlighting emerging focus fields in port performance-related studies. A co-occurrence analysis for the country was performed to identify the density of research activities in different countries. In the co-authorship analysis for the country, the minimum number of documents was set as 75 to get the overlay of visualization of the top 20 countries, and the country-specific citation minimum threshold was zero, considering the score of the average number of publications per year. Further, the co-occurrence of the keywords was analyzed to create the network using Louvin’s algorithm while limiting the number of nodes to 30 and the minimum number of edges to 0.

4 Results and analysis

In this section, the visualizations of bibliometric data based on citation metrics, co-citation, and co-occurrences are discussed along with bibliometric data analysis comprising the trend in publications, publication subject areas highlights, country of research work, author analysis, collaboration, and the journals publishing the relevant articles, to derive meaningful insights.

4.1 Descriptive analysis

The keyword search in the database identified 2245 articles published collectively from 691 sources of scientific publications from 1979 till April 20th, 2024. Of 4189 authors who contributed to publications in the port performance field, close to 29% had international co-authorship, and 274 had single-authored publications. The annual growth rate was 10.62%, and average citation was 20.24 per document. The descriptive summary of the bibliometric data is given in Table 2.

Table 2 Bibliometric data descriptive summary
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4.2 Trend of publications

Descriptive analysis of the bibliometric data shows a phenomenal annual growth rate of 10.62% in research publications related to port performance. The trend of published articles, along with the mean total citations per year from the first article published in 1979 till 20th April 2024, is shown in Fig. 1. There has been a spike in the number of publications since 2007, as indicated in the figure, and the number of publications has exponentially increased after that, suggesting that port performance is one of the most focused research areas in the recent decade.

Fig. 1
figure 1

Publication trend and citations from 1975 till 2023

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Ahrens' [61] novel research on the engineering performance of ports outlined the importance of management training through audio-visual techniques for improving port performance in developing countries. The trend of core engineering-related performance studies continued till Thomas [62] discussed the strategic management of ports and their development. Roll et al. [63] introduced the application of the DEA methodology in port performance comparison with a sample of 20 selected ports. Later, a noticeable surge in port performance studies started after Lin et al. [64] studied the operation performance of major container ports in the Asia–Pacific region and applied the DEA approach to evaluate the operational performance of ports based on their operation efficiency.

4.3 Subject area of publication analysis

The percentage share of the articles published in different subject areas of research is shown in Fig. 2. “Social Sciences,” “Engineering,” and “Business, Management, and Accounting” areas contribute more than 50% of the overall and are followed by the “Environmental Science,” Decision Sciences, and Economics, Econometrics and Finance,” and “Computer Science,” subject area and so on, out of which “Business, Management, and Accounting” areas account around 12%. Other areas include “Earth and Planetary Sciences,” “Energy,” “Mathematics,” “Agricultural and Biological Sciences”, “Arts and Humanities,” “Materials Science,” “Multidisciplinary,” “Chemical Engineering,” and “Psychology.”

Fig. 2
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Subject-wise publication share

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4.4 Journal of publication analysis

The distribution of the articles published in journals is shown in Fig. 3 for journals that have published more than 30 articles. “Maritime Policy and Management” journal is the leading source, with about 156 publications, followed by “Maritime Economics and Logistics” and “Sustainability” journals, together contributing to 5% of the total publications to date. “Research in Transportation and Management,” “Asian Journal of Shipping and Logistics,” and International Journal of Shipping and Transport Logistics” are closely competing with only one-third of the publications from the “Maritime Policy and Management” journal.

Fig. 3
figure 3

Top publishers with more than 30 publications

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To get a deeper understanding of the growth of sources, source dynamics were analyzed using a trend line, as shown in Fig. 4. Accordingly, it was identified that although “Maritime Policy and Management,” “Maritime Economics and Logistics”, “Sustainability”, “Research in Transportation Business and Management”, “Asian Journal of Shipping and Logistics”, “International Journal of Shipping and Logistics”, “Ocean and Coastal Management”, and “Transport policy” are the leaders in terms of total publications in the given order. Phenomenal growth was achieved by the “Sustainability” journal, which was at the bottom in 2007 and has shown exponential growth since then, reaching the third position in annual publications growth, overtaking the “Research in Transportation Business and Management” journal.

Fig. 4
figure 4

The trend of annual publications in top sources

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4.5 Author publication and citation analysis

The publications from the leading authors based on their number of publications and their citations are shown in Fig. 5. Lam JSL occupies the top position, with 27 publications commencing with the first publication in 2006. At the same time, the top author with the highest citation is Cullinane K, with the first publication in 2002 and contributing 21 publications in the last 20 years. Six of his publications in 2006 alone have received 822 citations so far.

Fig. 5
figure 5

Number of Publications and Citation to Publication ratio for top authors

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The authors’ collaboration network diagram is shown in Fig. 6. Some top authors, especially Cullinane, Pallis, Lam, Chen J, Ducruet, and Song, collaborate highly, leading to higher quality publications with increasing citations.

Fig. 6
figure 6

Author's network diagram

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4.6 Country of research analysis

The distribution of articles published across the top 15 countries based on publications and based on citations is shown in Figs. 7 and 8, respectively. China has the highest contribution, close to 24%, followed by the US and UK, with 8.6% and 4.6% of publications, respectively. Somensi et al. [50] also highlighted China as the highest contributor with the most significant port performance-related studies. India-centric publications are merely 3.47%, a mere 15% of that of China, which has 571 publications, followed by the US and the UK, with 205 and 110 publications, respectively. China is again the leader in citations with 8116 citations, followed by the US and UK 5189 and 4819 citations, respectively. However, Spain overtook Italy with 1843 citations from 93 articles, with 1628 citations from 94 publications.

Fig. 7
figure 7

Country-wise publication

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Fig. 8
figure 8

Country-wise citation

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The scatter plot in Fig. 9 shows China, the USA, and Korea leading mainly with single-country publications, compared with Singapore and the UK, which have more multi-country collaborated publications. Among the top 10 countries in collaboration aspects, India has higher single-country publications and only a few multi-country collaborated publications.

Fig. 9
figure 9

Scatter plot of single and multi-country publications

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4.7 Co-authorship and country-collaboration analysis

We considered the publications where the minimum number of publications was set as two, and the maximum number of countries counted as 25. Thus, among the 105 countries published, 77 meet this threshold. When calculating the total strength of the co-authorship links with other countries, only the countries with the greatest total link strength will be selected. The visualization of country-wise coauthorship and publication network in Fig. 10 shows that China has the highest density compared to other countries, indicating intense research on port and port performance.

Fig. 10
figure 10

Country-wise overlay of co-authorship

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4.8 Impact metrics analysis

The “Research Metrics Guidebook” provides a comprehensive list of metrics to assess the research impact at various levels, including journal, article, author, and affiliated institutional level productivity, citation, and collaboration based on scholarly content in the Scopus database [65]. Table 3 shows the citation impact metrics since 2018.

Table 3 Research impact metrics (extracted from Scival)
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“Field-weighted citation Impact” (FWCI) metric is a comparative metric that calculates the citations received by a document compared to the expected citations. It is a normalized bibliometric indicator that factors in the type of document, subject area, and publication period [66]. As we can see, the FWCI has been fluctuating; overall, it is at 1.12, indicating that the impact is 12 percent above the global average. Further break-up analysis on the authorship impact, as shown in Table 4, suggests more than 50 percent impact above the worldwide average of international collaboration. Industry-institute collaboration has significantly increased in 2024. “Outputs in Top Citation Percentiles” shows that 11.5 percent of the publications are in the top 10 percent. International collaboration has seen close to 30 percent collaboration over the years. The top fifteen country impact metrics, as shown in Table 5, indicate China is leading with the highest number of views and citations, along with an FWCI of 1.85, suggesting they are 85 percent above the global average. Spain, India, and Indonesia are 15, 18, and 36 percent below the global average.

Table 4 Collaboration impact metrics (extracted from Scival)
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Table 5 Country impact metrics for the top 15 based on publications (extracted from Scival)
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4.9 Co-occurrence analysis

The co-occurrence of the keywords was analyzed for keywords having a minimum of 40 occurrences to create cluster-based density visualization based on the weight of occurrences, as shown in Fig. 11. The core subject areas with the highest occurrences in the field of port performance-related studies are “Data Envelopment Analysis”, “efficiency”, “simulation”, “container terminal”, “port competitiveness”, “port governance”, “port management”, and “sustainability”. DEA and efficiency are the most weighted labels in the performance-related studies, with counts of 55 and 53, respectively. DEA and efficiency labels were followed by a simulation of the performance of seaports and container terminals and then the constructs related to performance, such as competitiveness, governance, management, and sustainability practices. In the computations text analysis of Sung-Woo et al. [49], the LDA output indicated DEA methodology as the most weighted term.

Fig. 11
figure 11

Density visualization of co-occurrences using VOSViewer

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4.10 Keyword analysis

The scatter plot in Fig. 12 with size measures showing the frequency count of the top trending words indicates that the trending words with the highest frequency in the last ten years are “port operations”, followed by “Container terminal”, “Data Envelopment Analysis”, “efficiency”, and “Sustainability” with the count as 341, 168, 155,136 and 92 respectively. Automation has been the trending word in recent years, with the previous years trending with the COVID-19 keyword, followed by performance, port automation, and economic development.

Fig. 12
figure 12

Top Trending words

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4.11 Thematic evolution analysis

Thematic evolution using a longitudinal map (alluvial graph) divides the timespan of the research field into slices of time duration prescribed based on the developments in the field. It illustrates the continuation and discontinuation of identified themes, thus explaining the conceptual structure of the field of interest [67, 68]. The thematic evolution shown in Fig. 13 demonstrates the evolution of the themes with three cutting points in the years 2008, 2014, and 2020. 2008 was set as the first cutting point as the publications trend showed an exponential increase after 2007. Then, the remaining cutting points were set as equal intervals to assess the thematic evolution. The word count was set to default as 200, with a minimum cluster frequency of 5, the number of labels for each cluster as 4 with a minimum weight index of 0.1, and thematic analysis using the Louvain algorithm.

Fig. 13
figure 13

Thematic evolution since 1979 using R-bibliometrix package

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Callon et al. [69] developed the co-word analysis technique based on the centrality and density matrix to analyze and explain word interactions in any research field over some time. According to Cobo et al. [57], the thematic map comprises four quadrants on which the themes are placed based on the centrality and density of the themes over the years. Centrality demonstrates the theme's importance or relevance within the given study area, whereas density represents the development of the theme over the selected timespan. The bubbles in the graph indicate the size of the occurrence within the cluster, comprised of interacting words demonstrating the co-occurrence network. Each quadrant has its characteristics based on the degree of centrality and density measures. Motor themes are those of high importance and development happening in the field. Niche themes are, by and large, isolated and highly developed combined with negligible, low, or limited importance. Emerging or declining themes are of low significance, and the density of the theme needs to be vigorously developed. Basic themes are characterized by high-importance and relevant and low-density themes. They are reasonably crucial for research since those topics still need to be fully developed and, therefore, potential issues for conducting future research [57, 69,70,71]. The recent 4th stage of the thematic map is shown in Fig. 14 for the 2019 to 2024 time span.

Fig. 14
figure 14

Thematic map of the 4th stage from 2018 till date using R-bibliometric package

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The thematic map resulted in nine clusters in the 4th stage, as tabulated in Table 6, summarising the themes and the related topics associated with each cluster.

Table 6 Themes for different clusters according to thematic map
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The theme with the highest centrality, complimented with high density, is “sustainability” among the topics mapped. To get more insight into the theme of “sustainability” topic identified, the trend of sustainability keywords in the previous two decades was visualized as shown in Fig. 15. Through the review of literature, it was also determined that the surge in usage of sustainability terms in research started after the pioneering work of Yap et al. [72], who initiated the focused discussions on sustainability-related topics, and after that, the usage has steadily grown exponentially.

Fig. 15
figure 15

Frequency Trend of Sustainability keyword

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5 Discussions

This study focused on bibliometric analysis of port performance-related studies based on the bibliometric data available on the Scopus database. This article critically examined bibliometric data of studies related to the performance of ports to explore the evolution, identify trends of articles published from 1975 till April 20th, 2024, the leading authors, top journals, impact metrics, and leading countries in terms of publications, and thereby highlight the research directions on port performance studies. From the trend of publications, it is evident that there has been a significant spike in the number of publications after 2007. After that, it has been exponentially increasing in concurrence with the findings of Pallis et al. [8], indicating that port performance is one of the highly focused research areas in recent times with over 10 percent annual growth rate. OConnor et al. [5] also highlighted the growing desire of policymakers and stakeholders in port performance evaluation and policy development, keeping in mind the interests of the public as well. The average citations were over 20 per document; however, the citations fluctuated with irregular peaking and flattening patterns. The timespan from 2000 to 2007 saw the highest number of citations and, after that, has been moderate but more significant than the rate of publications over the years except for the last two years, where the citations are yet to pick up due to the recently published articles. A review of publications gives insight into the fact that the articles are predominantly on port efficiency-related studies, with many articles starting to focus on DEA methodology application on port efficiency and port performance evaluation studies. Other studies [49, 50] also found that DEA-based studies have the highest number of publications and citations.

Among the various pre-defined subject areas of port-performance-related publications in Scopus, “Business, Management, and Accounting” contributes close to 12 percent, about half of the contribution in the “Social Sciences” subject area and, indicating “Business, Management, and Accounting” as a highly potential subject area for focused contribution in the port performance related field. Somensi et al. [50] also highlighted the need to enhance the research on business management. Among the sources of publications, “Maritime Policy & Management” leads the race in publications, with close to 7 percent of the publications. Our findings concur with the observations of Somensi et al. [50], who found similar results in their systematic literature review on the performance of the port topic. In their content analysis study, Notteboom et al. [49] highlighted 267 articles published in the “Maritime Policy & Management” journal, and the leading and continuous contributions of studies related to port were highlighted in the journal. Therefore, “Maritime Policy & Management” should be one of the primary journals researchers must subscribe to for notifications and regularly track updates on port research. The publications in “Maritime Policy & Management” are equal to the publications in “Maritime Economics and Logistics” and “Sustainability” journals. In the source of publication analysis, “Maritime Economics and Logistics” and “Sustainability” were identified as the sources with the highest growth rate for publications related to port performance. These two journals were at the bottom during 2000 and have shown exponential growth, especially the “Maritime Economics and Logistics” journal, which has reached second in annual publications growth, closely followed by the exponentially growing “Sustainability” journal, which has been gaining momentum since 2015. The “Sustainability” journal is growing steadily and exponentially compared to other trailing journals behind “Maritime Policy & Management”. The findings of Zhou et al. [73] also confirm that “Sustainability” and “Maritime Policy & Management” journals are the leading journals in port-related studies.

Among the authors contributing, Lam JSL, Notteboom, Song DW, Pallis, Ng AKY, Yang Z, and Ducruet C are a few critical leading authors with the highest contribution and co-citation in port performance-related studies. Zhou et al. [73] have a fascinating insight into the changing pattern of research hot spots in port-related studies and their associated dynamics. The study of Wang et al. [35] also identified LSL Lam as the most productive contributor with the highest number of publications. The collaborations network shows collaborations happening in some pockets within the US, UK, some parts of Europe, and South Korea to a greater level, thus taking international collaboration to 30% share. Although the US is ahead of the UK in publications, the normalized FWCI for the UK is higher by 30% at 1.75 compared to the US. It is worth highlighting that in addition to the multi-country-author collaboration, industry-institute collaboration is also improving and uplifting the impact further. Analyzing the country of publications, with about 20% contributions, China is the only developing economy in the leading countries of publications and citations, followed by the US, UK, Korea, Spain, and Italy. However, regarding citations, the UK has dominated other countries with the highest citations, followed by China and the US. This finding confirms the past conclusions [35, 73], where China was identified as the leading country regarding the number of publications, followed by the US and South Korea.

Density visualization of co-occurrences categorized the keywords into 3 clusters centered around the port operation, container terminal, and efficiency topics. The port operations-centered cluster had related keywords: performance assessment, competitiveness, sustainability, sustainable port development, decision-making, and policy. The container terminal-centered cluster had container cargo handling and computer simulation aspects. Lastly, the port efficiency-centered cluster had DEA, benchmarking, and productivity aspects. In the top ten labels based on occurrence frequency, DEA and efficiency are the most weighted labels, which aligns with the findings of the past conclusions [49, 50]. An overview of existing literature on port performance research also shows the studies were predominantly based on applying DEA methodology to compute the efficiency of the port, simulation modeling followed by critical dimensions such as port competitiveness, port performance, and sustainability, along with port governance and strategic management. DEA and efficiency labels were followed by a simulation of the performance of seaports and container terminals and then the constructs related to performance, such as competitiveness, governance, management, and sustainability practices.

Remarkably, thematic evolution shows the absence of DEA methodology after the cutting point in 2018, where it peaked and was later taken over by the sustainability theme. The sustainability theme started to evolve in 2013, far below DEA, and attained the top position from 2019 to 2024. The DEA theme, which has evolved since 2008, has been taken over by the port performance theme since 2019. The thematic analysis has also shed light on the themes revolving around the port hinterland theme, which have evolved through DEA methodology and recently, since 2017, into sustainability-related themes along with port performance. Container terminal and port governance have been themes that have continued to exist since 2008. The “COVID-19 pandemic” and “automatic detection systems” (AIS) were the latest themes that have explicitly evolved. As the entire world faced the wrath and impact of the global pandemic, the port industry was also not left free, and many studies [74,75,76,77,78] have evaluated the impact of COVID-19 on the port sector. Alongside this, most industries have adopted automation technologies to overcome the challenges and effects of the pandemic. This phenomenon is confirmed by the top trending words “automation” and “technology adoption” in 2023 and 2024. The application of robotics and other AIS in port operations became eminent, leading to many studies [79,80,81,82] exploring innovative applications and opportunities for automation and digital technology adoption. Even the keywords analysis indicates that technology adoption and automation have been the topics that have been highly discussed in recent times.

Yang et al. [81] also highlighted the increasing popularity of AIS in their review work on AIS and big data in maritime research. Ashrafi et al. [83] discussed the design of games to address various contain terminal problems. They proposed using virtual and augmented reality and Global Positioning System (GPS) technologies through simulation games in the dynamic port industry that can train and develop professionals who handle port planning, operations, and management. Meanwhile, Lee et al. [84] underlined the crucial role of AI and computer vision technology in response to dynamics in the port industry, specifically focusing on intelligent traffic management and parking space and container operations optimization in maritime ports. Applications of AIS and IoT through the “Smart Port” concept were detailed by Rajabi et al. [82] to overcome the challenges in port operations in the dynamic environment within which the port operates. Similar to the Industry 4.0 framework, the new-age innovative automation and robotics applications in seaport operations were conceptualized under the Shipping 4.0 framework in the study of Muhammad et al. [79].

The most trending words with the highest frequency in the last five years were identified as “Sustainability”, similar to the findings of Sung-Woo et al. [49], who highlighted the term as a core focus area in port-related research since 2010. They reviewed port-related research works applying the computational text analysis approach to the articles available in both the Scopus database and WoS database related to port research and published in international journals indexed in the Science Citation Index and Korea Citation Index also highlighted the need for sustainable port development and more focus on environmental sustainability alongside the development of port competitiveness. A similar finding was underscored by Wagner (2019) in the bibliometric data-based study on port cities. Sustainability is the new theme that has taken center stage, with a high density of publications and high importance and greater centrality, indicating the relevance of the studies in the current context. Most recent studies have spotted sustainability in the maritime industry as a topic of focused interest, as pointed out by Lee et al. [85], ever since the term was used at the first Earth Summit in 1992. It is emphasized as the need of the hour, supported by SDGs of the UN’s 2030 Agenda on emission reduction and sustainable maritime operations that have put significant pressure on maritime seaports, thereby demanding regulator compliance and sustainability reporting. Sustainability and intelligent ports were part of the motor theme cluster, indicating the theme of high importance and development happening in the field. AIS and ML were part of Motor cum niche cross-over themes indicating they are developed in isolation but are niche in nature. Similarly, the blockchain technology keyword in the niche theme is a highly developed concept, but it is isolated from the application in port in the development and growth stage.

We identified some of the major theoretical foundations that were adopted in port-related studies, such as “Business model innovation theory”, “resilience theory”, “resource dependence theory” and “stakeholder theory”. Ashrafi et al. [83] adopted stakeholder theory to synthesize the drivers of sustainability in maritime ports in the systematic review study. They discussed the sustainability strategies grouped into different clusters based on multi-stakeholder perspectives to integrate into port planning and operations as a response to the changing industry dynamics. Denktas-Sakar et al. [86] adopted the “resource dependence theory” to conceptualize a framework to integrate the relationships between the supply chain and port stakeholders to identify the impact on the sustainability of ports. Giudice et al. [13] adopted the “Business model innovation theory” and “resilience theory” to determine the innovative technologies and digitization of port operations as a solution for the economic, environmental, and social sustainability of ports in line with the description of Elkington [87] who coined the “Triple Bottom Line” foundations of sustainability. No specific definition of sustainability has been universally accepted, even though many have attempted to define it [88,89,90,91]; however, there is a common understanding from different schools of thought [88, 89] that sustainability encompasses most frequently related dimensions which are termed as the three pillars of sustainability have respective practices, viz economic sustainability practices, environmental sustainability practices, and social sustainability practices, that facilitate and lead towards sustainable development through practicing these practices. Recently, Jugović et al. [32] highlighted the emerging concept of a green port governance model of adopting sustainability practices in the port. Many studies [92,93,94,95] defined sustainability practices as the practices that aid organizations in developing opportunities and, at the same time, managing the three dimensions of organizational processes—economic, environmental, and social aspects in value creation over the long term.

Furthermore, Bjerkan et al. [96] highlighted the need for more port sustainability-related studies and empirical research on port sustainability. Adding to that, Lim et al. [97] also emphasized the importance of sustainable port performance in their systematic review of port sustainability and performance-related studies. They raised the flag on the focus of extant studies, mainly on environmental sustainability, and the need for more importance placed on social and economic sustainability in research studies. Multiple studies [98,99,100] have pointed out the uncertainty and lack of clarity among industry professionals and other research-oriented consultants and academicians on approaches to excel in sustainable performance and whether there are any significant positive results on performance due to sustainability. This considerable gap must be addressed and indicates the dire need for research incorporating sustainability concepts within the framework related to port performance. Many studies [14, 49, 101, 102] also acknowledged sustainability as one of the primary factors contributing to port competitiveness and performance enhancement. The report by UNCTAD [1] highlights the expectations of ports to consider sustainability aligned with port performance through strategic and operational steps as it has become a priority in overall maritime shipment. The report also opined that ports operating with higher sustainability have greater chances of attracting investments and increased support from various port stakeholders. Lim et al. [97] also highlighted the importance of sustainable port performance in their systematic review of port sustainability and performance. They mentioned the focus on only environmental sustainability and the need for more importance on social and economic sustainability in research studies. A similar emphasis on the ecological sustainability of green and sustainable ports was found in other studies [103, 104]. However, their studies also mentioned incorporating sustainability's economic and social dimensions in future research. Lee et al. [85] also outlined the need to explore the methodologies adopted in sustainability-related studies in their proposed future research directions.

Even though Sung-Woo et al. [49] highlighted quality and sustainability as the focus areas of port-related research since 2010, [99] opined that sustainability is an emerging concept that has yet to be overlooked. They also raised doubts about practitioners' and researchers' need for more clarity on whether the sustainability concept can yield positive results or has been successful. Broccardo et al. [100] also highlight the concern and crucial gap of need for clarity among academicians and researchers on the excellence that can be achieved in sustainability and performance. Further, in the review of tools and technologies work by Bjerkan et al. [96], empirical data-based research on the sustainability of ports was demanded due to the need for more sufficient studies related to experiences on implementation and associated challenges in port operations. More importantly, empirical data-driven research on sustainability-related topics and port performance will be critical to the growing body of knowledge.

Summarising the above discussions and findings, the insight drawn indicates that sustainability” is the most highlighted and evolving theme in recent years in port performance-related studies. [105] also pointed out the increased focus and evolution of sustainability in the context of society, industry as well as regulatory bodies in line with the argument of Broccardo et al. [100], who highlighted the concern and gap of lack of clarity among academicians and researchers on the excellence that can be achieved in sustainability and performance and emphasizes on addressing this crucial gap. Further, although companies are becoming increasingly involved in sustainability [106], academic researchers still need to make clear how to excel in sustainability and performance [98], thus highlighting a gap that must be addressed. This has resulted in a gush of publications on topics related to sustainability, as highlighted by [107].

6 Conclusion and future research directions

To the best of the researcher's knowledge, this study is novel due to its holistic coverage of the span of publications and growth and the thematic evolution of publications in maritime port performance-related studies. The bibliometric exploratory data analysis of articles published from 1979 to April 2024 was conducted to review the trend, explore the existing characteristics of port performance-related studies, and identify opportunities for future research. The increasing number of publications related to port performance indicates the extreme importance and focus on the performance of ports and related topic areas, especially from 2008 onwards.

The study contributes in the following ways. Firstly, it contributes to the overall understanding of the introduction and growth of port performance-related studies worldwide. Secondly, it provides exploratory data analysis on key characteristics such as the occurrence of keywords, research subject areas, top publishing journals, and country-wise research publications. Lastly, the findings give possible future research directions and opportunities. This is also a pioneer study that demonstrated the use of Python software and relevant packages for creating advanced visualizations using bibliometric data and the Bibliometrix package of the R-programming tool.

The study and the outcome discussions are bound with limitations, as in most research, and future research can address the shortcomings. Primarily, this study was limited to articles published in the Scopus database alone. Even institutional ranking agencies like Quacquarelli Symonds (QS) and Times Higher Education (THE) are adopting indexing matrices from Scopus due to its popularity and reliability of peer-reviewed publications in reputed journals. However, future research could integrate articles from other databases like WoS, ProQuest, IEEE, and Google Scholar for a holistic view of research publications available in other leading scholarly databases. An extended scoping review study can be conducted to understand better the underlying themes and the antecedents of port performance variables. Also, the studies should be focused on port management, competitiveness, and sustainability constructs to keep in line with the growing number of studies on these important and relevant labels related to sustainable port performance management. As recommended by Jeevan et al. [14], topic modeling, also termed LDA, to uncover the specific themes in port performance can be explored for further thematic research and comparing the studies between countries. Further, the digital and technology revolution has given way to innovative technologies and automation systems that aid resource optimization in various port operations and management. The extent of AI and ML applications supported with big data and blockchain concepts could also be explored for technology-aided sustainable development.

Despite the limitations mentioned above, the study contributes to the body of knowledge in terms of the evolution and trend of ongoing research in port performance, the leading journals of publication, publication citations, the most prolific authors, the co-authorship and occurrence network, top frequently used labels and topics, the thematic evolution and subject areas of study which will be of significant review and reference to researchers, academicians, and industry practitioner giving future directions of research on port performance and increased focus on a sustainability theme.