Social integration can be understood as the frequency and quality of interactions with colleagues (other doctoral students or faculty members) from the student’s department outside of the workplace and about matters other than academic ones (Golde 2000; Meeuwisse et al. 2010; Van Rooij, Fokkens-Bruinsma & Jansen 2019). Holmes and Rockinson-Szapkiw (2020) defined SI as the student’s satisfaction with the nature and quality of non-academic interactions between students and professors inside the programme.

International doctoral students’ first contact with their university department and its staff happens at admission, upon arrival at the institution and the commencement of their educational programme. This interaction continues throughout their studies (Brooman & Darwent 2014; Hughes & Smail 2015). It was discovered that positive interactions with departmental members and peers increase the likelihood that IDS will persevere and succeed in their doctoral projects, demonstrating that departments significantly impact student integration into the social environment of universities (Zhou & Okahana 2019). Scholars assert that positive student–department interactions facilitated students’ integration into academic disciplines and departments, a crucial factor for doctoral retention and completion (Cockrell & Shelley 2011; Zhou & Okahana 2019). Researchers argued that doctoral student retention required integration and participation in disciplines (Golde 2005) and academic departments (Herzig 2002). Other researchers found close relationships among departmental members and doctoral students were productive in helping students select dissertation committee members, which is crucial for the timely completion of doctoral programmes (Wao & Onwuegbuzie 2011). Thus, it is unsurprising that departmental academic support, such as foundation language courses for IDS, was associated with their success (Gardner 2008; Greene 2015).

Furthermore, doctoral completion was positively correlated with departmental activities and attitudes towards students (De Valero 2001). In addition, IDS who participated in engagement activities within the department, such as student groups and associations, experienced stress reduction and improved completion rates (Kearns, Gardiner & Marshall 2008). Other stream studies revealed high adaptability to the social systems of the university in which IDS are enrolled reduces attrition (Ellis 2001; Gardner 2007; Lovitts 2001).

Studies have found a high correlation between SI and success, development and contentment (Bair & Haworth 2004; Lovitts 2001; Shin et al. 2018). Individual factors, the microenvironment (such as the department, programme, classmates and professors) and the microenvironment influence the completion of doctoral degrees (Lovitts 2005). Researchers discovered that contacts with other faculty members and quality mentoring, encouragement and constructive criticism are among the most significant predictors of doctoral students’ satisfaction, persistence and general welfare (Gardner 2007; Lovitts 2001; Vekkaila, Pyhältö & Lonka 2014). For instance, Weidman and Stein (2013) discovered an association between the number of interactions between faculty and students and their involvement in research initiatives. Cockrell and Shelley (2011) revealed a substantial association between support systems and student happiness, indicating that doctoral programmes should improve support systems to reduce student attrition. Espino (2014) discovered in a study of minority graduate students that doctorate students benefited from socialization in academic contexts and support from their families, communities and graduate environments. Vekkaila et al. (2014) found that doctoral students’ perceptions of participation in and belonging to academic communities affected their positive experiences, well-being, contentment and persistence in doctorate studies. According to Piepenburg and Beckmann (2021), IDS who are not properly absorbed into their university’s social and intellectual culture will abandon their chosen field of study. According to reports, a lack of social interaction is one of the primary reasons German IDS drop out (Isleib, Woisch & Heublein 2019; Piepenburg & Beckmann 2021).

Considering the numerous positive effects of SI on the success of IDS, the literature has emphasized the department’s and faculty’s role in enhancing SI. Rigler et al. (2017) reported that isolation was a major factor in the attrition of doctoral students. Through their departments, doctoral programmes must create effective offline and online socialization opportunities for students to combat student isolation. According to the best practices within departments in institutions, Rockinson-Szapkiw et al. (2014) and Stallone (2011) reaffirmed that cohort models, social networking technologies and study or collaboration groups were effective ways to increase socialization among doctoral students. Janta, Lugosi and Brown (2014) focused on how departments can enhance doctoral students’ SI. Among the interaction opportunities cited by the researchers are welcome parties for new participants, social gatherings to commemorate the achievement of significant milestones, lunchtime seminars that combine food and academic discussion and other social gatherings. According to Merola et al. (2019), institutions should prioritize enhancing the social capital of students through techniques such as small-group instruction, which promotes interaction and academic performance. They further indicated that interventions that can improve students’ social capital and academic integration include working in groups or pairs during class and promoting peer tutoring.

International doctoral students’ SI is also unique to the discipline of study and research group status. The discipline, and its organizational structure in the university via a department, serves as the focal point for the student experience (Golde 2005). Vekkaila et al.’s (2014) research revealed that behavioural science doctoral students had a low sense of community involvement. The authors attributed this to the study style followed in their field. They underlined that the behavioural sciences are a subset of the soft sciences and are occasionally characterized by solitary research in libraries, archives or the field. Golde (2005) found that doctoral students in the natural sciences have high SI, which is in line with an earlier study by Chiang (2003). Walsh (2010) reported that IDS in engineering and science had difficulty integrating with the student body because of their rigorous schedules and cultural and communication differences. A subsequent study (Gardner 2010) discovered that doctoral students in English and oceanography were more socially integrated.

A recent study by Antilla, Sullanmaa and Pyhältö (2021) found that full-time domestic students felt lonelier and more insecure than domestic part-time students. They underlined that in contrast to full-time doctoral students who largely rely on the researcher community, having many responsibilities at once may shield part-time students from the social isolation or solitariness that has frequently been reported in related doctoral studies. Antilla et al. (2021) also pointed out that doctoral students who worked primarily or partially in a research group experienced loneliness more frequently than those who worked alone. This resulted in students working in research groups having higher expectations for social support and a sense of belonging than students working alone.

Other studies comparing SI between domestic and international students include Cena, Burns and Wilson (2021) and Spencer-Oatey et al. (2017). Only a few have examined these differences using large sample size, like this study. The study of Terentev et al. (2021) indicated a high attrition rate among Russian doctoral students. Yet, the preceding literature demonstrates a few studies identified in the broader context investigating SI among doctoral students based on nationality (domestic and international), the discipline of study and several years of study. There is a general lack of studies in the Russian context on this research topic.

Tinto (1993) used the lens of integration to describe the phenomenon of doctoral student attrition. He emphasizes the importance of students’ social and intellectual integration within their universities for determining their perseverance in doctoral programmes (Tinto 1993:50). He distinguished two unique integration systems: academic and SI, and described both. Academic integration is defined as students’ exposure to the research world and academic environment, whereas SI is defined as students’ interactions within the university’s social structures (Tinto 1993). He indicated that students enter university with various personal characteristics, including nationality, prior educational background and personal goal commitments. The successful interaction of these characteristics and university characteristics results in adequate integration. According to him, when students are thoroughly incorporated into the social systems of their host universities, their retention and perseverance in higher education improve significantly. He asserted that students who positively interact with their university environment are more likely to stay and eventually succeed in their studies and vice versa. This means that university structures must-have features that immediately make students feel accepted, engage them in university activities and provide a supportive environment for students to speak to one another, supervisors and other university employees.

Tinto’s theory was used to understand how various parts of interactive experiences within university departments vary between domestic and international doctoral students in various years of study and students in different fields. In this study, the nationality of students (domestic and international), field and year of study are considered individual attributes. In the departmental environment, which consists of other students, staff are the institutional attributes. The theory is used to analyse the effect of the interplay of these institutional and individual attributes on students’ social well-being. Students perform better in situations that: (1) promote student-to-student connection; (2) promote student-to-staff engagement; (3) treat all students fairly; (4) promote a sense of belonging; and (5) actively engage students. While this theory was developed at the institutional level, the authors believe it is worthwhile to apply it at the departmental level to increase the understanding of what institutions can do to improve student retention and reduce dropout rates among doctoral students and what individual departments can do.

A cross-institutional online survey was used to analyse doctoral students’ views on SI experiences during their studies at Russian universities. This survey was conducted in May – June 2021 on behalf of the Russian Ministry of Science and Higher Education under the project ‘Scientific and methodological support for the development of quality management system of higher education in the conditions of coronavirus disease 2019 (COVID-19) pandemic and after’.² The survey’s main goal was to analyse the challenges and opportunities for developing doctoral education quality at Russian universities during the pandemic. The questionnaire covered the following topics: (1) satisfaction with the university learning conditions and services, (2) characteristics of interaction with a supervisor and other university staff and satisfaction with this interaction, (3) main obstacles during the doctoral study and (4) professional goals and plans. Questions about SI and its different dimensions were at the core of the second series of questions (interactions with a supervisor and university staff).

The targeted sample for the survey was all doctoral students who had studied at Russian universities at the time of the survey. To access the respondents, the authors used letters of support from the Russian Ministry of Science and Higher Education, which were delivered to all Russian universities via the Ministry’s electronic system. Letters were addressed to rectors of universities and asked to share the link with their students. Participation in the survey was voluntary.

A total of 4454 doctoral students from 249 universities participated in the survey, which equals 9.0% of all doctoral students at Russian universities. The main characteristics of the sample are presented in Table 1: 91.2% of respondents are domestic students and 52.6% are male. Most of the doctoral students were in their first year of study (38.7%).

To measure the SI experiences of doctoral students, the authors used six the following questions, which were formulated in the form of statements: (1) ‘I have friends in my department’, (2) ‘I feel like I belong to the department’, (3) ‘I am proud to be a doctoral student of my department’, (4) ‘My department creates a welcoming and supportive environment’, (5) ‘I can always talk (in person or remotely) with my department’, and (6) ‘Faculty of my department/school/institute treat me fairly’. All questions were measured on a five-point Likert scale (ranging from 1 – strongly disagree to 5 – strongly agree). The authors used a four-point Likert scale (ranging from 1– my chances are high to 4 – I don’t think I will be able to defend my dissertation in five years) to evaluate international students’ expectations about the defence period. Lastly, the authors measured international students’ satisfaction with the quality of their programmes using a four-point Likert scale (ranging from 1– satisfied to 4 – dissatisfied).

After attaining the desired response threshold, the survey data were analysed separately based on six dimensions of SI. A five-point Likert scale (ranging from 1 – strongly disagree to 5 – strongly agree) was used to assess the themes of this research. The number of items used to measure each of the themes is presented in Table 2. The chi-square analysis method was used to analyse the experiences of domestic and IDS regarding the various aspects of social interaction within their university departments. The mean SI scores were then compared between domestic and IDS.