Volunteering has played a key role in the historical development of communities. It is an act of civic engagement that involves pro-social, planned and long-term behaviours with the aim of altruistically benefiting other individuals or groups in a particular organisational setting (Penner, 2002).

In the university context, volunteering is formal due to its organisational characteristics, through programmes managed by higher education institutions (HEIs) through their services or departments in collaboration with non-profit organisations (United Nations Volunteers [UNV], 2015). In general, volunteering programmes make it possible to articulate processes of collaboration and reciprocity between students, institutions and social organisations that benefit all the actors involved (Haski-Leventhal et al., 2020). In view of the challenges posed by the 2030 Agenda for Sustainable Development, volunteering expands and mobilises the university community to provide an effective response to global challenges (United Nations, 2021).

The development of transversal competencies -called in research soft skills, transferable skills or generic competencies- has become a crucial factor for the employability and social inclusion of university students in the current context characterised by globalisation, digitalisation, social exclusion, unemployment and precariousness of European and especially Spanish youth (García-Álvarez et al., 2022). These can be defined as a "dynamic combination of cognitive and meta-cognitive, interpersonal, intellectual and practical skills" that "help people to adapt and behave positively so that they can deal effectively with the challenges of their professional and everyday life" (Haselberg et al., 2012, p. 67).

In European policies, volunteering is a recurring training strategy in search of more opportunities to promote young people's social participation and employability by developing competencies in a lifelong learning approach (European Parliament and Council of the European Union, 2021). In the same way, universities have added to their agendas, alongside volunteer, service-learning or entrepreneurial initiatives, work placements or internships for students to gain experience in real learning environments (Evans & Yusof, 2022; Holmes et al., 2021).

In this sense, the Conference of Rectors of Spanish Universities (CRUE, 2021) has highlighted the need to keep working on the development of undergraduates' skills, not only through teaching projects, but also through other actions such as volunteer work. The aim is to improve their skills (upskilling) or acquire new skills (reskilling) for effective action in uncertain environments.

Reflecting the public interest of voluntary activities, the scientific literature contains numerous studies on the impact of such activities on participants' satisfaction, physical and mental wellbeing, self-awareness and self-reflection, altruism, intercultural competence, democratic participation, academic performance, moral development, social responsibility, employability, career development and higher levels of self-efficacy (Evans & Yusof, 2022; Haski-Leventhal et al., 2020; Holmes et al., 2021).

Overall, studies on the link between volunteering and the development of transversal competencies have focused on non-formal learning contexts, i.e. initiatives organised by non-profit organisations or other public or private institutions (cf. Santos Rego et al., 2018; Souto-Otero, 2016). As a result, there is less evidence that highlights the impact of these experiences from the management of university services (i.e. Khasanzyanova, 2017), particularly in the Spanish context.

In light of the above, this study aims to analyse the transversal competencies that students develop through their participation in volunteering programmes managed by higher education institutions in Spain. In this sense, the study addresses a main research question (RQ): What are the transversal competencies that students develop through their participation in volunteer activities managed by university services?

This research is the result of the specific collaboration agreement between the Universidade de Santiago de Compostela, Universitat de Girona and Fundación Mutua Madrileña for the development of the study "Volunteering and Social Participation in University Studies". Ref. (2022-CL060).

This paper is based on a non-experimental, exploratory and descriptive study. A non-probabilistic purposive sample was chosen for the research. For this purpose, five universities located in different parts of Spain and with similar volunteer services were selected: Universidad Autónoma de Madrid (UAM), Universitat de Girona (UdG), Universidad de Murcia (UM), Universidad Pablo de Olavide (UPO) and Universidade de Santiago de Compostela (USC). The participants are students registered in the databases of the services of the universities involved in the study, who participated in volunteering experiences between the academic years 2018-2019 and 2021-2022. The sample for the study is made up of 373 university students (79.6% female; 19% male; 1.3% other) who have carried out voluntary work in one or more academic years during their academic career. As regards the profile of the sample, it is worth noting that there is a notable presence of students from the field of Social and Legal Sciences (46.7%), having participated in these experiences during a single academic year (65.6%) in the following areas of volunteering: social (42.9%), social-health (15.8%) and educational (13.4%). The instrument is based on an ad hoc questionnaire for young volunteers at universities. Specifically, data are collected on the profile of student volunteers, motivations for volunteering and satisfaction with the university services. In addition, the instrument has a Likert scale (1=not at all; 5=very much). Its purpose is to assess the extent to which student volunteers have developed a set of transversal competencies that have been identified in the scientific literature as essential for young people's employability and social inclusion. Similar studies in the field (Santos Rego et al., 2018; Souto-Otero, 2016) and in European higher education institutions, as in the case of the Tuning project (González & Wagenaar, 2003), were considered for the design of the scale. The psychometric analysis of the scale was carried out using Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA). All indices showed a proper adjustment. The final scale resulted in 16 items. The instrument was administered at two points in time (September and October 2021) through the online tool Microsoft Forms. Participants were informed of the voluntary and anonymous nature of the instrument. Data processing was carried out in accordance with EU Regulation 2016/679 and Organic Law 3/2018 on personal data protection. IBM SPSS version 27 software was used for data coding and statistical analysis.

In general, this paper has examined the extent to which students who participate in voluntary activities managed by Spanish universities develop transversal competencies. The data clearly indicate that participation in extracurricular activities contributes to the improvement of young people's human capital, with effects on academic, civic and professional dimensions (Evans & Yusof, 2022; Haski-Leventhal et al., 2020; Khasanzyanova, 2017; Santos Rego et al., 2018). Specifically, the results show that the most developed transversal competencies are teamwork (M=4.39; SD .92), problem solving (M=4.19; SD=.88), planning, coordination and organization (M= 4.14; SD=.92), and initiative (M= 4.14; SD= .91). International work (M=3.16; SD= 1.44) and using technology (M=3.17; SD=1.40) were rated lowest. Combining these results, in line with similar studies in national and international contexts, participation in voluntary work contributes significantly to the development of young people's transversal competencies, in particular: teamwork, problem-solving, creativity, organisational skills or entrepreneurship (Khasanzyanova, 2017; Santos Rego et al., 2018; Souto-Otero, 2016). However, the scarce development of competencies in the context of digitalisation and internationalisation calls for a greater effort on the part of higher education institutions in their management, with a wider range of options. This applies to international volunteering and digital volunteering, which have been shown to benefit young people's personal and professional development (Jones, 2010; Park & Johnston, 2017). In general, this work has shown the need to consider volunteering programmes as a key educational strategy for universities to work towards greater social inclusion and student employability. This is particularly important in view of the high levels of unemployment and social exclusion among young people in Spain. However, we must not forget the third mission of the university, which considers the transfer of knowledge and social responsibility as the main axes of its action, in which volunteering plays and should always play an important role.

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