Keywords

1 Introduction

The outbreak of the COVID-19 pandemic has generated multiple and complex challenges for individuals, organizations, communities, and authorities. It generated significant disruptions, affecting many areas of life in most of the countries and territories. One of the sectors that has been strongly impacted is the higher education sector, where teaching and pedagogy, evaluation, as well as the experiences of students and teachers have changed profoundly from the beginning of the pandemic to the present. In many ways, the COVID-19 pandemic and the closure of universities and then switching to online education had potential negative effects on the students’ physical, academic, financial, and psychological well-being (Kecojevic et al. 2020).

While social distancing and preventive measures disrupted the pre-existing educational practices, reopening of schools as part of relaxation brought additional challenges as new approaches have been embraced by teachers, students, and educational institutions as coping strategies (Pokhrel and Chhetri 2021).

2 Literature Review

As many changes and challenges impacted the higher education sector in a very short time span, more and more researchers channeled their work toward these topics of study. Some of them have focused on revealing challenges and impacts for teachers, students, and educational institutions, while others have emphasized future developments of the higher education sector triggered by the COVID-19 pandemic. The impacts have been investigated in various geographical contexts and educational environments, including work-based learning components and tutoring-based systems (Pérez-Jorge et al. 2020), as well as particular fields of study such as medical education (Abbasi et al. 2020). The response of educational institutions to the crisis has also been targeted by many studies (Andrew et al. 2020).

Reviewing the existing evidence on the effects of the COVID-19 pandemic on learning, teaching, and assessment strategies and practices, Khan (2021) identified several key themes in the scientific literature: digital learning, challenges associated with e-learning, emergency virtual assessment, the impact of COVID-19 at a psychological level, and development of collaborative cultures. In this context, new concepts and themes emerged in the research discussion related to the educational crisis during the COVID-19 pandemic, such as “emergency remote teaching” and “emergency virtual assessment” (Khan 2021).

One of the most important topics of research was related to the transition from onsite to online learning. The unprecedented rise of e-learning has been investigated in relation to student satisfaction and academic performance (Nambiar 2020; Keržič et al. 2021), teachers’ experiences (Nambiar 2020; Nilsberth et al. 2021), as well as the use and development of various pedagogical approaches (Doucet et al. 2020). The preparedness of educational communities for transiting to digital learning has been one of the most important research topics in this matter (Osman 2020). An important point of view is that digital education will be part of the new normal in education and will become more hybrid as the challenges experienced during the COVID-19 pandemic are overcome and transformed into opportunities (Olasile and Emrah 2020).

Educational inequalities were also addressed, with numerous evidence pointing out that the negative effects are distributed unequally across social groups (Engzell et al. 2020; Maldonado and De Witte 2022). Coping strategies have been unequally available for students, teachers, and schools from various socio-economic backgrounds. Resilience in the face of adverse conditions was higher among those more resourceful. The general view is that the COVID-19 pandemic has widened educational inequalities (Aristovnik et al. 2020; UNESCO 2022).

Another important subject of study for researchers has been related to the mental health of students. Studies have found higher levels of anxiety and depression among students due to restrictions and isolation (Chen and Lucock 2022), with negative effects on their academic performance (Di Malta et al. 2022). Moreover, studies show that universities did play an important role in supporting students’ well-being during pandemic times by providing the needed procedures and information (Sarasjärvi et al. 2022). While most of the scholars have been interested in the mental health of students, some studies focused on the mental well-being of teaching staff (Sipeki et al. 2022).

In this paper, we aim to provide a comprehensive overview of studies addressing the effects of the COVID-19 pandemic on higher education. We used bibliometric analysis based on the VOSviewer program to unfold the main occurring terms and subsequently themes through the more than the two years since the pandemic started.

3 Methodology

As stated above, our aims were to identify recurring themes and concepts in the scientific literature on higher education and its adjustments to the conditions imposed by the pandemic. Also, we wanted to observe how the themes and concepts changed and evolved during the three years since the beginning of the pandemic (2020–2022).

To achieve our aims, we conducted a bibliometric analysis of articles published and indexed in the Web of Science Core Collection database from 2020 to 2022. The criteria for selecting publications from the Web of Science Core Collection database were: to contain in the title “higher education” or “universities” or “tertiary education”, as well as “covid (-19)” or “corona (virus)”; to be indexed starting with 2020 till present; and to be included in the “articles” category. From the Web of Science, 1963 articles were initially extracted that contained the above-mentioned criteria. We excluded early-access articles, retracted papers, and book chapters. The final database had 1755 articles; the highest number of articles was published in 2021 (1087); 330 papers were published in 2020, while 338 articles were published so far in 2022.

In order to observe the themes and terms used in publications, we focused our analysis on the keywords of the indexed articles, as well as their evolution over the three years. Also, in order to observe the countries with the highest contribution of publications during the pandemic, we studied the co-authorship according to the country of the authors. To meet the study objective, but also to bring novelty to the bibliometric studies that address the pandemic, we used VOSviewer, a free software program, to create and analyze maps based on network data, bibliographic data, and text data. The software can use bibliographic data to explore co-authorship (by authors, organizations, or countries), co-occurrence (based on keywords), citations, bibliographic coupling, and co-citations (van Eck and Waltman 2021). Thus, the program simplifies the process of analyzing bibliometric analysis of scientific publications by journals, authors, organizations, keywords, titles, abstracts, etc. (van Eck and Waltman 2021). In our keyword analysis, nodes represent keywords, and lines link strongly connected words, namely words with many co-occurrences. Node spacing is based on the relationship between words and color with a particular cluster or group of words. Table 1 presents the parameters used to draw the maps for each step of the analysis. In the analysis on co-authorship by country, a node that was not connected was deleted from the chart, namely Bosnia and Herzegovina. We used the normalization association strength method in the analysis.

Table 1 Parameters for each map designed
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4 Results Interpretation

Most of the articles published and indexed yearly during 2020–2022 were under the research area of “Education & Educational Research” (cca. 20% of total number of articles), followed by “Public, Environmental & Occupational Health” (cca. 15%), the following positions fluctuating slightly from year to year (see Table 2). So, only by analyzing the top research areas of indexed articles we can observe a slight shift in the topics of research from health issues and how to manage pandemic in 2020 to how to make better use of technology in 2021, and then to psychological effects (probably of both health measures and use of technology) in 2022.

Table 2 Number of articles by research area and year of publication
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As presented in the methodology section, we started our exploratory analysis by drawing the map of the keywords from all the articles addressing tertiary education and the COVID-19 pandemic published in 2020–2022.

Five thematic clusters were generated, covering areas of research related to challenges that students and teachers faced in integrating and operating technologies and tools that support online education (cluster 1), mental health and psychological well-being (cluster 2), hygiene, infection control, and vaccination attitudes and opinions among medical students and healthcare workers (cluster 3), methodological designs used to assess effects, well-being and mental health (cluster 4), and pandemic measures (especially containment measures) and their potential health effects on students or the general public (cluster 5). Figure 1 also shows the short distance between clusters 3 and 4, as well as between clusters 3 and 5.

Fig. 1
An illustration of five different spherical clusters of words linked together. Clusters 1, 2, and 3 have a higher sphere volume than Clusters 4 and 5. Covid 19 has the highest sphere volume.

Source Web of science core collection database. Authors’ design through VOSviewer

Co-occurrence of keywords in articles in the period 2020–2022.

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Subsequently, we present the thematic clusters generated when analyzing the articles indexed year by year, aiming to better picture the puzzle of themes addressed by research articles addressing higher education issues during the pandemic.

For 2020, only four clusters of research themes were generated; the initial studies being largely focused on how students accepted and were satisfied with the shift to online education (cluster 1), general psychological impact of pandemics (cluster 2), students’ mental health (cluster 3) and students’ attitudes, challenges, and behaviors toward the trauma of pandemic (cluster 4). In conclusion, at the beginning, the themes were rather general and aimed at identifying different effects of the pandemic at the level of different organizations and individuals (Fig. 2).

For 2021, the same analysis shows a larger number of themes addressed by studies in the area. Ten clusters of keywords were generated, the focus of papers covering: experiences and risk perceptions of medical students and health care workers during pandemic (cluster 1), integration of digital technology in online teaching and learning and technology acceptance (cluster 2), engagement, motivation, and learning outcomes of online education (cluster 3), lifestyle (eating habits, alcohol use, fitness, etc.), effects of sedentariness and isolation (cluster 4), effects on mental health (cluster 5), safety behaviors and quality of life (cluster 6), digital literacy and public health (cluster 7), effects of mental health on academic performance (cluster 8), effects on internationalization of education (cluster 9), and quality of online education (cluster 10) (Fig. 3).

Fig. 2
Four different spherical clusters of words are linked together. Clusters 3 and 4 are grouped, while Clusters 1 and 4 are close together. Covid 19 has the highest sphere volume.

Source Web of science core collection database. Authors’ design through VOSviewer

Co-occurrence of keywords in articles in 2020.

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Fig. 3
An illustration of 10 different spherical clusters of words connected with each other. Clusters 1, 3, and 5 have large volume of spheres.

Source Web of science core collection database. Authors’ design through VOSviewer

Co-occurrence of keywords in articles in 2021.

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Fig. 4
7 different spherical clusters of words connected with each other. Clusters 1, 2, 3, and 7 have large volume of spheres.

Source Web of science core collection database. Authors’ design through VOSviewer

Co-occurrence of keywords in articles in 2022.

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The diversification of themes is expected to increase in 2022. The map designed only for the first months of the year 2022 evidenced seven clusters covering the following themes: technology acceptance mainly among teachers (cluster 1), students’ mental health and academic performances (cluster 2), students’ mental health and quality of life (cluster 3), beliefs and attitudes on vaccine among students and particularly among health care workers (cluster 4), institutional developments of universities during pandemic (cluster 5), satisfaction with online teaching (cluster 6), and negative effects of remote learning (cluster 7) (Fig. 4).

Figure 5 gives us an overview of the international collaborations in the scientific literature on higher education during the pandemic, thus demonstrating both the countries that have the most significant contributions of articles, as well as how countries are connected. Five clusters were generated according to the co-authorship. From the diagram, we can observe that most countries are strongly connected in terms of co-authorship, the countries with the highest infusion of articles being the USA, China, England, Spain, and Saudi Arabia. China, the USA, Australia, Japan, as well as several countries from Eastern Europe, but also from the Middle East and Africa are grouped in the first cluster. The second cluster includes especially Western and Southern European countries. The third cluster contains countries mainly from the Middle East and Africa. The fourth cluster specifically includes Spanish-speaking countries, while the fifth cluster comprises, for the most part, Eastern European countries. Clusters 1 and 2 are located in a very short distance, demonstrating on the one hand that most of the research on the COVID-19 pandemic was conducted in the countries covered by these two clusters, but also how strong were the research partnerships during the analyzed period of time.

Fig. 5
5 different spherical clusters of countries are connected together. U S A has the largest volume of spheres.

Source Web of science core collection database. Authors’ design through VOSviewer

Co-authorship analysis by countries on articles in the period 2020–2022.

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5 Conclusions

The paper summarizes through the use of bibliometrics how universities were affected and responded to the COVID-19 pandemic, the analysis by year evidencing the increasing focus on psychological well-being and mental health as the time passes. The analysis of the main research areas indicates that scientific interests shifted from focusing on health effects to addressing the use of technology and then on the psychological and social effects of the pandemic. Most of the keywords under the clusters analyzing all the publications from 2020 to 2022, point to the negative and long-term effects of pandemic and social distance measures in higher education sector, such as psychological and physical effects, infection control, or attitudes toward vaccination. Also, the efforts that institutions made to shift to online education, the technological acceptance, and digital literacy were extensively and regularly addressed.

In 2020, the research was rather general, focusing on students’ satisfaction with online education, mental health among students and the general population, and students’ attitudes, challenges, and behaviors toward the pandemic. In 2021, alongside mental and physical health effects of the pandemic, the quality of education, quality of learning outcomes, and academic performances also started to be more and more addressed. Another specific topic of research in 2021 was related to medical students and health care workers, both with respect to vaccination, but also to the effects of pandemic on the mental health of professionals in the field. The analysis of the research published so far in 2022 revealed a diversification in themes with a focus on technology acceptance among teachers, vaccine attitudes, mental health, and academic performances among students and institutional changes and developments.

The collaboration analysis by country revealed that the highest volume of research on higher education during the COVID-19 pandemic came from the USA, China, England, Spain, and Saudi Arabia. In addition, four main clusters of collaboration of countries were identified.

The analysis can be further replicated when most of the papers published in 2022 will be indexed and extended by making use of other text mining techniques. The present research gives us insight into the scientific research on how higher education institutions reacted and adjusted to the pandemic challenges and the main research trends in this field during the 2020–2022 period. Research themes reflect on the one hand the public agenda during the pandemic, both the general one and the education agenda, but also uncover the long-term social and psychological implications of the measures undertaken to contain the COVID pandemic.