Service-Learning in Europe. Dimensions and Understanding From Academic Publication

Service-learning began within the framework of the New School in which constructivist experiential methodologies were particularly important following various studies, such as those by John Dewey and his “Learning by Doing” approach. From then on, this pedagogical practice has spread all over the world at varying rates. In Europe it was slower to spread than in the Americas. In this regard it is especially interesting to look at the current state of the matter. The object of this study was to analyze the academic publication in Europe since the year 2000 with a detailed bibliographic review of publications with roots in Europe. We examined the main databases and used an analysis matrix with various content levels. We found that service-learning has different names in Europe, and that there have been uneven epistemological advances depending on the countries examined. We also noted that, in general, it was about higher education that most literature had been published. One of our significant conclusions was the exponential growth of contributions over the last 20 years, particularly in Spain, which produced the most academic literature on this topic. We believe that service-learning faces the challenge of effective consolidation based on educational quality criteria, and which includes combining elements of virtuality, reality, and academic rigor.


INTRODUCTION
The unforeseen events of 2020 have threatened both advances in society and the ideas that lie behind them. To the already well-worn crisis of the welfare state something which is non-negotiable for some and mortally wounded if not subject to reinvention for others we have to add the social crisis that is a consequence of SARS-Cov-2. Numerous political, healthcare, environmental, and social challenges are forcing old inflexibilities to adapt to new realities in a global sense. Education is of course no exception. Challenges that only a short time ago seemed obvious to us in a sea of uncertainty (Caride, 2017) and which needed to be approached through various lenses beyond the four walls of the classroom must necessarily be reviewed again (Úcar, 2018). In the particular case concerning us, for example, the ubiquitous shift towards Information and Communication Technology (ICT) and its connection with service-learning Sotelino et al., 2020;Tapia, 2020) that must now take place to deal with an unprecedented scenario of confinement. In this regard, the focus once again is placed on who will be responsible for educating more creative, more flexible professionals and citizens who will know how to respond to continued uncertainty (Arbués et al., 2012), and also on the determinants of how, which not only ties our hands but also (forcibly) opens our minds.
Technological and methodological responses to this situation have appeared in various educational areas which have been validated through practice, but with pedagogical specialists also at the forefront. Service-learning is one of the methodologies which is gaining importance in the various levels of the school system, and also in non-formal educational spheres (Sotelino et al., 2019). This pedagogical approach, increasingly used in Spain , aims to bring together curricular competencies with contextualized service in the community (Puig et al., 2011;Santos-Rego et al., 2015;Deeley, 2016). In this way, participants consolidate their learning from their experiences and the reflections that occur. More specifically, in terms of the latter, these types of projects have their origin in the Chicago school at the hands of John Dewey, who had already studied cognitive meaning from experience-based learning (Giles and Eyler, 1994;Sotelino, 2015;Gonzalez-Geraldo et al., 2017) which catalyzed what he called "reflective learning" or "reflective inquiry" (Saltmarsh, 1996).
The European history of service-learning is marked by some milestones. In 2003, the European Service-Learning-Asociation (ESLA) was created, the first meeting of which was attended by representatives from Germany, the Netherlands, Sweden, Norway, and Spain. One significant event at this level was the CIVICUS European research project, promoted by the Vytautas Magnus University in Lithuania-a country whose servicelearning roots are directly tied to the United States-the framework of which explored forms of cooperation between universities, businesses, institutions, local government, and organizations (Santos-Rego, 2013). From that point onwards, service-learning started to develop rapidly in Europe, although unevenly distributed by country . In addition to projects, in Europe there have been in-depth studies that have looked at the quality, dissemination, and development of this practice and its educational efficacy. In the United Kingdom, Spain, Switzerland, the Netherlands, and Ireland, to name some clear examples, various statewide general and subject-based (by educational level or sphere) networks have appeared. In recent years international networks have advanced the development of service-learning in Europe, such as The European Network of Service-Learning in Higher Education launched in Galway in September 2017. In 2019 the European Observatory of Service-Learning in Higher Education was created. Similarly, The International Association for Research on Service Learning and Community Engagement (IARSLCE), created in 2005 with the aim of promoting research and discussion about service-learning and the participation of the community (Sotelino, 2014;IARSLCE, 2016). Currently in Spain, together with the various research groups and experts dedicated to service-learning, there is a general network encompassing the various fields and educational levels, together with other more specific networks (Batlle, 2013).
Service-learning currently has sufficient scientific support to indicate that it is a route to acquiring relational and cooperative skills while not diverting attention from the curriculum or educational project of reference. We should not forget that service-learning is, above all but not to the exclusion of all, a teaching method. This idea is similar, but differs in terms of the activism and political positioning applied, from the substrate of critical pedagogy which it has, to the religious reminiscences present in some countries, such as Spain (Igelmo and Jover, 2019). However, nowadays, to look more at the present and the future of service-learning in the new normality and the more desired post-new normality (derived from the influence of , there needs to be a balance between the different contributions, and future challenges need to be faced that affect this methodology. In this regard, it is worth asking questions that will guide our work. Is the academic production about servicelearning the same throughout Europe? In which field, research area or European country has service-learning progressed most in terms of publications? These questions must be answered in order to locate the state of service-learning in Europe, knowing those areas of study, educational levels and European countries where it is being implemented to a greater extent.
In order to this, the objective of our study is to review the academic literature from Europe about service-learning from the last twenty years . We say from Europe rather than in Europe because our searches will locate European experts who may have been published in non-European journals, not surprising given the American roots of service-learning.
Before describing the study, it is a good opportunity to briefly look at the conceptual and pedagogical aspects of servicelearning. This will help us understand some of the keys which have driven the expansion of this methodology and the academic literature about it.

SERVICE-LEARNING: CONCEPT AND PEDAGOGY
The term service-learning was coined and began to be conceptualized in North America at the end of the 1970s in the framework of a proliferation of both obligatory and voluntary youth service programs. It was born out of the New School pedagogical movement occasionally also called active schooling where experiential constructivist methodologies were particularly important following various studies. The thinking of William James and John Dewey and their premise of "Learning by Doing" was especially influential (Tapia, 2012;González-Geraldo et al., 2017). Paulo Freire also played an important role, as at that time the North American tradition of experiential learning combined with the Latin American social experience. From that point on, this pedagogical practice has spread all over the world, albeit unevenly.
The methodology of service-learning has been most developed in the United States and that is where most of the literature on the topic can be found. Because of that, it would be a mistake not to refer to the United States development of service-learning, as it arose there, it was constructed there, and it spread from there to many countries (Santos-Rego, 2013). The United States was where the term service-learning was first used, in 1967 when William Ramsay, Robert Sigmon, and Michael Hart used it to describe a local development project implemented by students and teachers from the OAK Ridge Associated Universities in Tennessee, although the expression was not consolidated until the first Service Learning Conference, which took place in Atlanta in 1969 (Sotelino, 2015).
In Latin America it is possible to find good examples of service-learning with governmental and social support in countries such as Mexico, Argentina, Chile, Uruguay and some Central American countries. In Central and South America there is a consolidated tradition of service-learning both in schools and universities, as well as in other kinds of civic-social organizations. It may be understood as the citizen response to the profound crises many Latin American countries suffered through in the 1980s and 90s, leading to many community service projects being implemented by various institutions. Service-learning arose as a resource that helped make more sense of these community minded practices. In this respect, the role played by CLAYSS (The Latin American Center for Service-Learning) was not trivial, as they drove the spread of this methodology to various countries (Tapia, 2010).
European development was slower than in the Americas, and one might even say that in some cases it was a direct consequence of American development (Mažeikienė, 2019), but its production is being extensive, especially in countries where its expansion is increasing. In Europe, the cradle of service-learning was in English-speaking countries, and was linked to the idea of community education (Luna González, 2010). In recent years projects such as the Europe Engage Project have appeared, supported by the European Union with the objective of promoting the use of service learning. This project emphasizes that, at the university level, for example, future professionals must be trained through practical learning linked to the social environment, helping to solve problems for the community (Europe Engage, 2014). Even so, as McLeod and McLeod (2015) noted, the first experiences of this in some Eastern European universities were not until 2004, and we can currently talk of a two-speed Europe; one group of countries in which service-learning is consolidated (United Kingdom, Ireland, Spain, and Germany), and another group where it is emerging (Austria, Belgium, the Netherlands, and Portugal, to name a few). This is a duality which may lead to service-learning becoming less visible in countries where it is more accepted through a process called blackboxing in which, paradoxically "the more science and technology succeed, the more opaque and obscure they become' (Latour, quoted in Mažeikienė, 2019).
From a methodological perspective, service-learning combines two methods from active pedagogies: learning through experience and action in service to the community. As Castle and Osman (2003) noted, service-learning offers opportunities to integrate learning, research, and communication at the same time as offering a service, intensifying the social aspect of education.
Both elements, learning and service, are key to understand what service-learning is. By overlapping, they produce a new reality to which reflection is added as the combining element that enriches the significance of the experience (Campo, 2008). If a reciprocal relationship can be achieved between the two components, the academic learning will have an impact on the delivery of a quality service to the community, and at the same time the service will strengthen and enhance the students' learning, providing benefits to both the students and the community from improvements at the cognitive and social level (Mella-Nuñez et al., 2015;Santos-Rego and Lorenzo, 2018).
Throughout its existence, service-learning has accumulated various definitions. Bringle and Hatcher (1996) understood it "as a credit-bearing educational experience in which students participate in an organized service activity that meets identified community needs and reflect on the service activity in such a way as to gain further understanding of course content, a broader appreciation of the discipline, and an enhanced sense of civic responsibility" (p. 222).
For Eyler and Giles (1999), service-learning is a form of experience-based education in which learning is constructed through a cycle of action and reflection. Students work with other classmates in a process of applying what they have learned to issues in the community and, at the same time, reflecting on their experience of trying to achieve improvements for the community and increasing their own understanding and skills. Puig et al. (2007) understood service-learning as an educational approach that combines learning processes and serving the community in a single, well-articulated project in which the participants learn while working on real needs in their environment with the aim of improving it.
After examining nine definitions, De la Cerda et al. (2009) identified seven common traits. They are: responding to social needs or carrying out an action to benefit the community, learning something, performing a service, having a meaningful experience, performing activities of reflection, collaborating with other social institutions, and contributing to training for citizenship. In turn, they analyze the service-learning journey based on their definitions. Finally, Furco and Norvell's (2019) synthesize that service-learning is an innovative pedagogical approach that integrates meaningful community service or engagement into the curriculum. They also indicate that the service-learning brings together resources, academics and the community whereby all became teaching resources, problems solvers and partners.
The variety of possibilities and the many practical approaches combine to give rise to multiple definitions such as those mentioned above. Its geographical demarcation and the scope of application also influence this question. What seems clearer, and where all the definitions coincide, is that service-learning seeks experiential learning while carrying out an action that improves community life, the natural or cultural environment, or intervenes in specific areas such as health or educational causes. Although each of the definitions are consistent with the idea of experienced-based learning, it is important to remember that activities that provide a service to the community are not always service-learning. As Furco (1996) noted, many service programs share similarities such as allowing students to get close to their future professional roles and to work on social and collaborative skills, or to explore their own interests. However, the idea of service-learning, which focuses on learning at the same time as service, should not be confused with other educational experiences which focus only on service or only on learning.
It is interesting to note that the spread of this "learning philosophy" has given rise to different labels in different areas; one might talk of "service-learning", in the United States, "Social service", in Mexico, "Practical Social Experience Semesters", in Colombia, "Educational volunteerism", in Brazil, "Community Service Learning", in Turkey, "Communal work", in Costa Rica, and "Learning Service", in Bolivia, etc. (Tapia et al., 2005;Kucukoglu, 2012;Alcón, 2014;Gezuraga, 2014). There are also differences within individual countries, such as the general use in Spain of the term Service-learning or Solidarity-Learning, although on some specific occasions the term "Learning and Solidarity Service" is used (Gezuraga, 2014;García-Pérez and Mendía, 2015).
On occasion, when referring to service-learning, concepts such as "voluntary", "community service", "field studies", and "community education" are used interchangeably, although in reality these terms do not always refer to the same thing. This, as Furco (1996) states, means that the student is faced with a certain terminological complexity when referring to these experiences.
Currently, and with the extensive published research, we can have some certainty of which experiences we can call servicelearning, and which are not. From the field of Educational Theory it is fundamentally a certain way of understanding learning based on exploration, action, reflection, and social responsibility. Far from being a merely instructive approach of accumulating knowledge, it requires the student to be the protagonist of their learning, and that fundamentally they only learn what they do and reflect on. This aspect, the reflection that all service-learning experiences should trigger and which therefore must be evaluated, is usually ignored when service-learning is used and understood from a biased perspective placing the service at the center. Service-learning is a methodology that addresses everyday issues and contextualizes learning in real situations (Uruñuela, 2011). The difference of service-learning from other methodologies such as internships, clinical experiences in health sciences, community research or field experiences, is that in addition to an explicit link with an educational plan or academic curriculum, there is a social commitment that entails the development of awareness ethics. Linking theory with practice and classrooms with professional surroundings allow students to approach a real professional learning environment (Naval and Arbués, 2016). In addition, as Howard (1998) noted, it is important to emphasize that service-learning will not occur if there is not a solid union between the demands of the community, the service that is needed, and linked academic learning.
The main learning outcomes of service-learning projects are not only in the content, but also the overall experience and personal transformation, allowing the development of many varied, complementary competencies in different aspects of the individual. In addition, it is important to highlight the acquisition of civic learning that implies the execution of responsibility with the reference community group, its needs, and its potentialities. In this sense, social, educational, environmental, cultural, neighborhood or health entities take on a special role by becoming co-educators of the participants in service-learning projects (Conway et al., 2009;Hatcher et al., 2017). Using this methodology combines learning various basic and specific competencies, such as working in interdisciplinary teams, interpersonal skills, ethical commitment, and critical reasoning (Agencia Nacional de Evaluación de la Calidad y Acreditación-ANECA, 2005). Studies and experience have shown that this methodology positively affects students in various areas, including motivation to study (Flournoy, 2007), civic responsibility and commitment (Hébert and Hauf, 2015), the development of critical thinking (Deeley, 2010), personal and interpersonal development (Eyler, 2000), the development of life skills (Fullerton et al., 2015), and ethical and moral awareness (Rhoads, 1998). The study by Warren (2012) showed that it is a methodology that improves students' learning compared to other previously used teaching methods. There have also been multiple studies that support the argument that service-learning combines several dimensions of learning in a single methodology: civic, academic, social and political (Novak et al., 2007;Celio et al., 2011;Yorio and Ye, 2012). Despite this, we must reiterate that the difference of the service-learning in relation to other dynamics of pedagogical work is the civic-social component that the participants develop in their bond with the community (Conway et al., 2009;Mella-Nuñez, 2019).
In summary, and as a proper definition, we believe that service-learning is a pedagogical methodology (with what this implies) that requires the explicit connection between curricula or educational plans and the performance of a community service in a single project. Thus, service-learning participants develop complex cognitive strategies that require questioning what they have learned, and their own role in the social and environmental framework.
Although the academic trajectory around service-learning is broad, there are many challenges that arise today, opening new avenues for researchers. We highlight two of them. The first one is the internationalization, as a connection between different physical spaces for the performance of services; and on the other hand, virtuality, adapting projects to new needs derived from greater interconnectivity between people (Santos-Rego et al., 2020). These are the lines that mark the future paths of the service-learning, without neglecting the advances in its optimal evaluation and maintenance of quality .
The didactic and pedagogical potential of service-learning seems clear. This may be why in recent years there has been such an increase in interest in implementing it and in the academic literature about it. Our study looks at exactly this issue, with the main aim of creating a diagnostic map of the European academic literature about service-learning. We believe this is not a trivial question for two main reasons. Firstly, examining European academic publication development in various countries will provide information about the current state of service-learning in Europe and that will make possible to establish international collaborative networks. Secondly, identifying important aspects of European academic publication, such as type of document, language, area of study or education level where it is implemented, will improve our understanding of this methodology and its impact. Both issues will help improve our research in the international context.
Below, we describe the study we performed and the results we obtained.

THE ACADEMIC LITERATURE ON SERVICE-LEARNING IN EUROPE
To carry out this study we reviewed the main international databases: Web of Science (WoS), Scopus, the Educational Resource Information Center (ERIC), and the Directory of Open Access Journals (DOAJ), in order to find documents related to the various aspects of service-learning (e.g., academic, social, community, cognitive). We followed a qualitative methodology using a matrix review method, followed by a quantitative analysis of the results. We used an analysis instrument created ex professo in which we established different levels of content.

Objectives
Our objectives were as follows: a. Determine how many academic publications there were about service-learning in the main international databases. b. Evaluate how the diffusion of the service-learning methodology in different types of publication has increased over time. c. Compare the academic literature, mainly in terms of research productivity and geographic variables.

Method
We planned a bibliographic document analysis using the main international databases (WoS, Scopus, ERIC, and DOAJ). These databases were chosen because WoS and Scopus are very significant international databases, while ERIC is one of the most important database in education and DOAJ include Open Access Journals.
Our research methodology has broad epistemological support. As Clausó (1993, p. 11) noted, this concept has been dealt with by many authors and has developed in step with the documentation, one can state that there are two tendencies with respect to how it is conceived, one which considers document analysis to include various phases, of which bibliographic description is one, and another which believes that document analysis must be exclusively considered as the description of content and not as a formal description. In our case we adhered to a quantitative description based on our objectives, laying out the current state of service-learning in Europe. Nevertheless, in a more qualitative approach, we also examined educational fields and/or educational levels of study referred to the various documents.
At the applied level, we created an instrument in the form of a table in which the rows correspond to the levels of analysis created, and the columns to those criteria we examined in each stratum. They are as follows: number of documents, document type (article, book, chapter, doctoral theses, other), language (English, Spanish, other), and country of publication. Secondly, and in order to have complete information where available in the databases, we also recorded, but not explored their content in depth, the number of publications per year and the research area or field they referred to.

Procedure
We established two search criteria referring our study objectives. We focused on reviewing documents published between 2000 and 2020 (September). In this case, it has been considered this range of 20 years because, after trying to make searches with other range of years, it was possible to check that the vast majority of documents were included in this period of time.
We also only looked at publications referring to European countries, and in the search criteria we restricted it to countries belonging to the European Higher Education Area (EHEA). We did not limit the publication language, as that would be an indicator in our subsequent analysis.
Once the general criteria were set, we established the different levels of document analysis. To that end, we considered the labels used for service-learning in different areas. Keywords used were taken after analyzing a significant number of potential options and checking which were mostly used in different documents related to the topic of this article. Finally, we establish two levels of filtering. The first one refers to the terms that most frequently name it ("service-learning" and "service learning"). At the second level, we choose terms referring to commitment to the community ("community engagement") and participation in it ("community service activities"). These levels of analysis were considered after checking that some documents about servicelearning (despite referring to the same reality) use the idea of participation and commitment to the community instead of just the term "service-learning".
In relation to the language, we have carried out the search only in English, because this is the most widespread language in academic publications. In addition, both keywords and abstracts of articles and other works are usually identified in this language. For this reason, regardless of the language of origin of the academic work, the existence of its translation into English is very common to favor its dissemination. The levels were as follows: • First level: • "service learning" OR "service-learning" • Second level: • "service-learning" OR "community engagement" • "service-learning" AND "community engagement" • "service-learning" OR "community service activities" • "service-learning" AND "community service activities"

Results
Following the bibliographic search, we give the results for each of the databases. The tables provide the data extracted from the document review. The results of the study, in addition to comparing the data from different databases, allowed us to gauge European interest in the service-learning methodology.

Web of Science-WoS (JCR)
The search engine for the Web of Science indexes a large number of publications, and allows classification using numerous filters, including year of publication, countries, languages, topic areas, type of document, authors, financing bodies, participating universities and many more, all of which is continually updated.
From the "Web of Science Core Collection" database, we gathered the data detailed below (note that the number in the data may be variable owing to the continual updating). More than 500 documents were identified using "service learning" or "service-learning" as the search term for the topic. This number changed depending on the combinations used for the search. If we added (OR) "community engagement", the number rose considerably to over 1900, however when we looked for both terms together (AND), it fell to below 20. The same happened when we added other combinations such as "community service activities", slightly increasing the number of hits when either term was used, but lowering it when both terms were used together (note that some documents were recorded as multiple document types simultaneously). In terms of publication type, articles stood out, with more than 300 compared to other documents such as conference papers, book chapters, or reviews. The results are given in Table 1.
In terms of the countries with the most published content about service-learning, the number varied depending on the combination of levels used. Looking at the keyword "servicelearning", the country with the most publications was Spain (291 documents) followed by the United Kingdom-England (68), Ireland (28), Turkey (23), and Germany (20). However, this changed when we used combinations such as "servicelearning" OR "community engagement", and "service-learning" AND "community engagement", with the United Kingdom leading the way. When we searched for "service-learning" AND "community service activities", Turkey had the highest number of publications. English was by far the most common language of publication, followed by Spanish and other languages as shown in Table 2 (please note that some documents are in more than one language).
In terms of production in the last 20 years as indicated by this database, there has been a notable rise, especially in the last 5 years. The first publications were in 2002, and there was a significant increase in 2015 with more than 50, then in 2019 there more than 100. So far this year (September 2020) more than 40 documents have been indexed.
The area of study producing most documents was "Education and educational research" (works on education, theoretical and applied) (345), followed by "Education scientific disciplines" (educational resources in the different scientific disciplines) (21), "Green sustainable science technology" (19), "Environmental sciences" (18), "Business" (14), "Environmental studies" (13), and "Management" (13). These research areas are which the database shows because every document covered by Web of Science core collection is assigned to one category or another depending on the journal where it has been published.
Lastly, the main collaborations were with the United States and Canada, where we found countries such as the Czech Republic, Kazakhstan, and Lithuania; a large proportion of their scarce publication on the topic was in collaboration with the aforementioned countries. 149 "Service-learning" AND "community engagement" 19 14 6 3 0 1 "Service-learning" OR "community service activities" 512 364 112 38 14 30 "Service-learning" AND "community service activities" 1 1 1

Scopus-SCIMAGO (SJR)
The Scopus database contains a significant number of publications and also allows the use of different filters, including country, language, type of publication, authors, financing bodies, annual publication, etc. In our search we found that the total number of articles returned varied depending on whether the "Title-Abstract-Keywords" search terms were "service-learning" or "service learning" alone (525 documents) or whether they were combined with other terms such as "community engagement" (2249/32 documents) or "community service activities" (529/0 documents). In this regard, the number of documents increased when "community service activities" was added as it includes Turkish publications that would not appear otherwise but which are about service-learning (which is called community service learning/experiences in Turkey). In all of the searches, most of the hits returned were articles, followed by book chapters and conference papers in similar numbers, then reviews and other documents such as books, editorials, letters, etc. This is detailed in Table 3.
There were also variations in country depending on the search terms used. Searching only for "service-learning" returned the most documents from Spain (176 documents) followed by the United Kingdom (139 documents) and Ireland (42 documents), and then other countries with five or fewer publications. However, when the search included "community engagement", the United Kingdom overtook Spain as shown in Table 4. Furthermore, in this database, the majority of documents found were in English, followed by Spanish, then other languages.
One thing which stood out was the growth in published documents about service-learning indexed in this database over the last 20 years , with a particular increase in the last 5 years. The first publication was in 2002 and there were fewer than 10 per year until 2008, when 18 publications were recorded. This rose gradually and then rapidly to around 50 in 2017/18 and 88 in 2019. This year so far 40 documents have been recorded.
Most of the documents were in the social sciences area (373 documents), which, in this case, was considered as a single research area because it was not possible to obtain the results by separate due to the characteristics of this database. Despite this, it is known that other subareas, such as "Education" or "Developmental and Educational Psychology" among others, are included in this category. Other popular areas were "Business, Management, and Accounting." (61), "Psychology" (53), and "Computer science" (52). We found smaller, although not insignificant, numbers of publications in "Engineering" (49), "Medicine" (44), "Arts and humanities" (38), "Environmental Science" (25), and "Nursing" (21). On occasion, one document could belong to multiple areas.
Finally, there were various collaborations between European publication overall and publication in other countries, mainly the United States. In some countries such as Bulgaria, Hungary, and the Czech Republic work on this subject was scarce and much, or all of it has been in collaboration with countries outside the EHEA.

Educational Resource Information Center-ERIC
The Educational Resource Information Center (ERIC) database is the most important database in the field of education sciences. It was created with the support of the United States Department of Education Institute of Education Sciences, the National Library of Education, and the Office of Educational Research and Improvement, indexing articles from around a thousand journals.
Before looking at the bibliographic analysis from this resource, it is important to note some limitations in its use that will help interpret the results. ERIC provides some predetermined filters that appear based on the search, grouping results depending on the relationships between publications. Although this makes rapid investigation easier, it also restricts systematic selection 158 90 "Service-learning" AND "community engagement" 32 18 5 6 2 1 "Service-learning" OR "community service activities" 529 365 62 69 20 13 "Service-learning" AND "community service activities" 0 0 0 0 0 0 and because of this, with ERIC was not possible to specified, for instance, the accurate year of the first publication or the most productive year. In this regard the general results we present are at a global level (Table 5), although in a second table we have selected the results more in line with our study objectives. It is also important to remember that ERIC only searches texts in English, which means a bias when it comes to work in other languages. This table refers to a global analysis given the nature of ERIC searches. However, there are some aspects that follow the trends that we have already pointed out. Most of the work is located in the United States and in the field of higher education, which is possible to be known because this database, in comparison to the others, shows results related to the education level. In addition, the academic publication obtained through the search for "service-learning" or "community service activities" stands out.
At this level of analysis, we looked at the European countries that most often appeared in this database ( Table 6). Because ERIC is limited to searching texts in English, it was clear that the United Kingdom and Ireland would dominate in the rankings, although Turkey's position is curious. The United States Department of Education database only shows the first 25 results, which leads us to conclude that publications from other countries are below that. It is also important to note that ERIC does not group by country, but instead by areas (states, zones, areas) where there are a series of studies under a single criteria, leading to the first positions being occupied by North American States. Additionally, it is necessary to take into account that it was not possible to obtain information about concreted fields because of the characteristics of the database.

Directory of Open Access Journals-DOAJ
Unlike the previous cases, the DOAJ is not a database but rather an online directory giving access to high quality scientific and academic journals. Its purpose is to increase the visibility of open access journals and make them easier to use, increasing their use and impact. The directory aims to be global, and covers all of the open access journals which use quality control systems. It includes publications from 133 countries.
It was founded in 2003 and initially administered by the University of Lund (Sweden). Nowadays it is managed by Infrastructure Services for Open Access CIC, a non-profit organization based in the United Kingdom. It is funded by donations from members and indexes around 15,000 journals and more than five million articles.
In this case, the only document type found by the search will be articles, although the directory offers the possibility of accessing information about the open access journals related to this topic. When searching, the directory offers some preset filters related to topic, publication, and year. However, it is not possible to filter by country of publication, which means it is impossible to determine which are European in origin. When using "service learning" or "service-learning" as the search term, the total number of articles returned was 684. This changed when adding other search terms. When additionally searching for (OR) "community engagement", the number of hits rose to 2039. However, when searching for the two terms together (AND) the number of hits fell to 60. The same happened when adding "community service activities" to the search term. Looking for either term gave 790 hits, whereas looking for both terms together gave only three articles. In addition, the same as happen with ERIC database, it was not possible to have access to information about research areas due to the filters that this database uses.
A total of nine open access journals published articles on the topic. They were published in the United States, Australia, and Indonesia, in English and in Indonesian. They were: United States: Partnership: A Journal of service-learning and Civic Engagement; Michigan Journal of Community Service Learning; International Journal for Service Learning in Engineering.

Keywords
European country 1st 2nd 3rd "Service learning" OR "service-learning" United Kingdom (301) Turkey (57) Others "Service-learning" OR "community engagement" United Kingdom (22) Ireland (13) Others "Service-learning" AND "community engagement" United Kingdom (7) Ireland (3) Others "Service-learning" OR "community service activities" United Kingdom (211) Others "Service-learning" AND "community service activities" Turkey (1) Others "Service learning" OR "service-learning" 7,996 6,322 203 457 1,014 "Service-learning" OR "community engagement" 1,008 797 26 62 123 "Service-learning" AND "community engagement" 289 257 9 10 13 "Service-learning" OR "community service activities" 6,826 4,660 202 420 1,544 "Service-learning" AND "community service activities" The fact that this number of journals provide open access to original papers on service-learning and community participation gives us an idea of the amount of research on the topic. However, the absence of open access journals at the European level is clear.
The search results are shown in Table 7.
The first article on the topic was published in 1997. Over the following ten years there was a gradual increase, with 116 articles published in 2012 and 383 in 2019. So far in 2020, there have been 229 articles on the topic.

Limitations
One of the strengths of our work comes from the broad study of international databases. However, like any study, it is not without its limitations. We are aware that the nature of the literature review we performed brings with it a limitation in how deep the analysis can be. We have presented a more quantitative and descriptive than analytical view. It is true that quantity does not necessarily mean quality but, after the results that are being found, it is possible to think that there has been an evolution. There is a significant number of researches by comparison with some years ago and these publications are registered in relevant databases, which means that they has passed a review process previously and, because of that, they are reliable and relevant.
The main obstacle we found was related to the differences between the databases, which apply different search filters, that is why they were analyzed by separated. We addressed this by balancing the levels of investigation and creating our own instrument to balance the analysis. The second limitation was also related to the nature of the databases, some do not reference autonomous city-states (The Vatican, San Marino, Monaco, etc.), and there were also issues around the topic classification of the work contained therein.
Finally, there were questions of interest we did not address but nor did we forget. Future lines of research may, for example, look more deeply into the researchers and research groups producing documents, as well as the institutions and the various financing bodies for service-learning. The content of service-learning programs themselves, now put to the test as social distancing makes certain community practices particularly difficult, would be another issue to address in a society where service-learning is ever more ubiquitous (Tapia, 2020).

DISCUSSION AND FINAL CONSIDERATIONS
The main objective of this paper is to study the evolution of service-learning in Europe, through academic publications. In addition, we have reviewed some questions such as place of publication or educational level/field based on the information provided by different databases.
In this sense, service-learning is already a reality in Europe in curricula at all educational levels as well as in other non-formal education projects. The progressive increase of the academic literature supports this idea, and as we noted previously, this is also demonstrated in the broad range of different types of publications we found, especially regarding higher education as it was commented on the ERIC results. Additionally, the presence of some associations like European Observatory of Service-Learning in Higher Education 1 (cited in the theoretical framework), the increasing existence of research projects about service-learning in higher education (that can be verified in the different resolutions of regional, state and European research projects 234 ) and different meetings and educational activities focused on higher education could presuppose that there is a tendency to implement this methodology in this educational level. Beside this, the general growing interest in this methodology was shown by the year on year growth in publications on the topic.
One of the main results, and which responds to one of the proposed objectives, is the prominent role played by Spain, which highlighted in the European publication on service-learning, followed by the United Kingdom, and Ireland. This has also been confirmed by other recent studies in which the production of literature in Spain was graded "exceptional" and "extremely high" compared to other European countries, avoiding the aforementioned blackboxing that threatens practices that become institutionalized (Mažeikienė, 2019). It is also worth

Keywords
Number of articles Journals Number Language "Service learning" OR "service-learning" 684 3 English (3) "Service-learning" OR "community engagement" 2039 9 English (5) Indonesian (4) "Service-learning" AND "community engagement" 60 0 "Service-learning" OR "community service activities" 790 3 English (3) "Service-learning" AND "community service activities" 3 0 1 www.eoslhe.eu 2 https://www.usc.es/apsuni/ 3 https://ec.europa.eu/programmes/erasmus-plus/about_en 4 https://www.fh-krems.ac.at/en/research/projects/service-learning-in%20europe/ noting that the United Kingdom stood out in publications linked to Community Engagement. These terms are related but they are not synonyms and a deeper look could distinguish in which educational context are they mainly being used it seems as though the domination of the United Kingdom and Spain in publication is waning and there are more publications in different countries and areas, notably Turkey, which appears in this ranking. Something else that clearly stands out was the number of publications that refer-due to their title, abstract and/or keywords-to the university environment, where the greatest growth and development has occurred in the last 20 years. At the macro level, publications referring to projects and studies in non-formal education were much more scarce than those to do with all phases of formal education, from infant to higher education. In relation to research areas, the filters of the databases make difficult to define which are more related to service-learning, even so, in general, it could be possible to assume that it might be Social Sciences and, specifically, areas of study related to education. The methodology called service-learning has different labels, which could be interpreted as different trends based on terminological, historical, social or even epistemological issues. Even so, and accepting a broad conceptualization of the servicelearning, the philosophy behind all of them points towards a common theoretical denominator (see González-Geraldo et al., 2017). In this regard we have been able to integrate the different aspects to produce a general map of the spread of service-learning in Europe. We found that the most commonly used labels were "service-learning" (both hyphenated and not), "Learning and Solidarity Service", and "community engagement". However, other options arose in the search referring to this experiencebased methodology as "community service activities" or "community service experiences/learning". Again, a deeper look could determine if these adjacent terms are being progressively used frequently, something that could help us to see if and how this methodology spreads and is considered not only geographically but also along time.
In summary, and to respond to the objectives of this paper, we confirm the development and progress of service-learning in Europe. At least in terms of academic production. Thus, and with the data presented, an evolution in research and knowledge transfer in relation to service-learning was confirmed, which is a clear symptom of how this methodology is also consolidating, specially within our higher education institutions. Although it arrived on the continent with relatively little fanfare, it seems that its academic spread is bearing fruit in Europe at two speeds. There has been uneven progress in different countries and academic fields, with the spread of service-learning having been weaker in some countries. At the present moment, there are various challenges that service-learning must face, and it must adapt to the coming virtualization, as well as develop better quality control for projects so that cognitive and sociocommunity objectives are met with rigor.
The current situation of strengthening the presence of servicelearning in the educational context and in social entities also poses challenges that must be faced. This includes the need to establish an appropriate theoretical foundation of its pedagogical dimension. It will be useful to understand service-learning as a teaching tool-a path towards a broader aim-in the framework of a community-based educational paradigm (Naval and Arbués, 2016) and not simply as a means to a laudable end that the service aspires to. This will help win the argument for its pedagogical contribution to a broad vision of education for social transformation. The contributions it can make to this transformation include the promotion of active citizenship, its contribution to social justice, and its contributions to the challenges of sustainability.
In terms of the civic dimension, including students' real, committed intervention in the search for common good is a fundamental educational mechanism for achieving comprehensive and holistic citizen education regarding all the dimensions of the learner. The concept of practical citizenship allows service-learning to be posed as an ideal methodology to achieve the education of a participative citizenry capable of contributing to the common good (Puig et al., 2011). The services performed in the various entities often contribute to civic education, as it helps improve political understanding, citizen responsibility, awareness and understanding of social issues, and express commitment to community service. Students end up contributing to the development and wellbeing of a community that requires intercultural and civic skills and abilities (Priegue and Sotelino, 2016).
All service-learning projects, when they comply with their basic requirements (such as the aforementioned reflection and subsequent assessment), have the potential to develop a vision of social justice. Students learn to question society from a critical perspective, and to analyze the situations that they will find in their lives with a reflective approach to these realities, where they come from, how to prevent them, how to deal with them, and the impact of service in improving unfair situations and in social change (Aramburuzabala, 2013). Thus, service-learning, as the data we found indicate, is a teaching tool that is mostly used in higher education, where the students are mature enough to better understand the complex reality of our time. It is reasonable therefore, to consider service-learning as an excellent teaching approach to make universities truly aspire to be institutions of higher education (González-Geraldo, 2014).
In terms of sustainability, it would be useful to train professionals to be able to use their knowledge, not only in the academic context, but also for social and environmental needs. This means addressing the entire process holistically, introducing competencies for sustainability transversally so that students learn to take decisions and carry out actions from sustainable criteria (CRUE/Comisión de Sostenibilidad, 2015). There is no doubt that service-learning is a potentially appropriate strategy to encourage the transformation and development of skills and competencies in students that are needed for the sustainable development of our societies (Vázquez-Verdera, 2015).
It is worth noting that service-learning is a methodology that has many proponents, including experts, teachers, and members of community organizations, who advocate its institutional use to promote, for example, knowledge transfer (Santos Rego, 2020). It stands as a methodology that will allow students and participants Frontiers in Education | www.frontiersin.org March 2021 | Volume 6 | Article 604825 in educational projects to gain new adaptive skills that will be indispensable in the historic times we are living through, and with which we will have to respond to the new needs thrown up by uncertainty. We believe that teachers at all levels should seek new ways to guide their subjects so that, in addition to learning specific content, students can develop social and civic values and incorporate skill-based learning (Naval and Arbués, 2017). Finally, as we showed, this paper contributes to identify how the European academic production increases along time and the countries in which this methodology is progressively developed. A clear symptom of the good health of this research framework within the European scholar community. But, of course, there is still a lot to say regarding the content of this academic production, their institutions and their research groups and researchers. Future lines of research in which quality awaits to meet quantity. Before concluding, we believe that we must incorporate a brief reflection because the year 2020 has implied a change in human relations due to COVID-19, restricting presence in the different educational processes (formal and non-formal), and therefore in the service-learning projects. This fact has led to the adaptation of this experiential methodology opting for a greater virtuality both in the field of service and in its pedagogical link (Tapia and Peregalli, 2020). Thus, The European Association of Service-Learning in Higher Education (EASLHE), in collaboration with the Latin American Pact for Human Quality Education (Palech), the European Observatory of Service-Learning in Higher Education and the National Distance Education University (UNED) have developed a Practical guide on e-Service-Learning in response to COVID-19 to support adapting Service-Learning courses to new reality (Albanesi et al., 2020). There are also multiple academic publications that have emerged in these months identifying the adaptation of multiple service-learning projects to the new needs arising from this pandemic (Red Española de Aprendizaje-Servicio, 2020; Beaman and Davison, 2020;Martínez-Vivot, et al., 2020;Morton and Rosenfeld, 2021). In this way, we can observe that this type of initiative can be adjusted to different realities, even the most extreme, as it has been the case of the outbreak of the coronavirus, we even reaffirm the words of Krasny (2020) when he tells us that social distancing is no reason to stop service learning, just do it online.
Finally, the path of service-learning in Europe is still under construction, but with this review we can see that the joint knowledge that is being built is increasingly solid. Now the challenge is clear, the service-learning must penetrate other educational fields, and even generalize its regular expansion in European countries. All of this cannot go against the quality of the initiatives, because in pedagogy, talking about quantity does not always mean an educational improvement.

DATA AVAILABILITY STATEMENT
Publicly available datasets were analyzed in this study. This data can be found here: Web of Science; Scopus; ERIC; DOAJ.

AUTHOR CONTRIBUTIONS
The AS-L author together with JLG-G have been working on the theoretical justification of the paper. These authors have carried out analyzes of the different databases, completing their interpretation. On the other hand, LG-D has been the person who has created the instrument for evaluating the databases, and making the inquiries in the different repositories. EA-R has contributed to building the theoretical body of the article, reviewing the entire content, and ordering the results obtained.