Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This is generally a well written and well organised article on an interesting and important area.

The literature review is generally sound, well expressed and well evidenced. Ecological systems approach is generally adequately explained but I think it would have been better to include a fuller discussion of other papers that have used this approach to explore volunteering specifically (Kulik,  2007; Axlund McBride & Lott, 2015) rather than citing other papers that had used this approach in an educational context.

There is a presumption in the literature review that almost all decisions to engage, sustain and leave volunteering are motivational. Quite a lot of the European data suggests that there may more be systemic challenges to student volunteering that is also contributing to a decline in many countries – financial hardship and student loans leading to a need for paid work, more hybrid and distance learning that can weaken a sense of community and participation in extra-curricular activities.

With regard to the research questions there is a statement about the mesosystem not being  included for ‘research method limitations’ – please explain more fully.

My more major concerns are methodological. If I have understood correctly the data corpus is rather small at under five hours of qualitative data.  I’m presuming participants were only interviewed once and multiple waves (section 2.2) meant recruiting and interviewing new participants?

I didn’t really have a very good sense of who the participants were. The inclusion criteria of individuals who ‘sustained’ volunteering arent very clear. Did the sample include those who had withdrawn from volunteering or who had changed volunteer positions. This would be helpful to know.

The analysis is generally rather shallow and descriptive. I’d recommend reading and citing some of the many more recent papers on thematic analysis by Braun and Clarke – they have clarified and explained their approach (and different variants) if you can offer a deeper and more interpretative account of the analysis. I actually feel that your approach is more in line with a qualitative content analysis. You seem to have identified and then quantified in most cases (with N and %) content units that fit with the ecological layers rather than something more inductive and thematic, and I think  QCA is a more plausible model. Most of the material in 3.1.1, 3.1.2, 3.1.3, 3.1.4, 3.2.1 and 3.2.2 summarises rather than analyses the data. I also wasn’t sure why there were no tables of quotations for 3.3 and 3.4.

Finally, I feel the Chinese context needs explaining a bit more – to what extent to cultural and university values promote volunteering. A few aspects did not make sense to me. Why is attending a PhD defence considered ‘volunteering’ etc.

Author Response

Comment 1-1: This is generally a well written and well organised article on an interesting and important area.

Author response: Thank you!

Comment 1-2: The literature review is generally sound, well expressed and well evidenced. Ecological systems approach is generally adequately explained but I think it would have been better to include a fuller discussion of other papers that have used this approach to explore volunteering specifically (Kulik,  2007; Axlund McBride & Lott, 2015) rather than citing other papers that had used this approach in an educational context.

Author response: Thank you for your comment. We have added the study of Axlund McBride and Lott (2015) to the Section 1.4. Now it reads: “EST was used to explore volunteering specifically. For example, EST-based research examined responses to volunteering as expressed in satisfaction with volunteering and burnout (Kulik, 2007), illustrating the theory’s applicability to volunteer behavior research. By adopting Bronfenbrenner’s ecological model of human development as a theoretical framework, Axlund McBride and Lott (2015) identified one multi-faceted campus environment associated with volunteerism among college women and investigated the experiences of both volunteers and non-volunteers in college.”

Comment 1-3: There is a presumption in the literature review that almost all decisions to engage, sustain and leave volunteering are motivational. Quite a lot of the European data suggests that there may more be systemic challenges to student volunteering that is also contributing to a decline in many countries – financial hardship and student loans leading to a need for paid work, more hybrid and distance learning that can weaken a sense of community and participation in extra-curricular activities.

Author response: We did address negative cases in the analysis. During the interviews, participants were explicitly asked about “experiences that motivated you to continue or, conversely, to withdraw from volunteering.” Furthermore, in Section 3.4, we specifically identified factors that hindered sustained participation, such as physical fatigue and inadequate financial subsidies.

However, given that the focus of this study was on the question “What Drives University Students’ Sustained Participation in Volunteering?”, participants tended to place greater emphasis on factors that strengthened their motivation to continue volunteering rather than on those that discouraged participation.

To clarify this point, we have added an additional paragraph to the Conclusion section.

“In addition, as the primary focus of this study was on factors driving participation in volunteering, relatively less attention was devoted to exploring inhibiting or constraining factors. Although participants were invited to reflect on barriers to volunteering, fewer responses were provided in this regard. As a result, the present findings offer a more comprehensive understanding of motivational drivers than of potential obstacles. Future studies may adopt a more balanced design to further investigate the interplay between facilitating and hindering factors.”

Comment 1-4: With regard to the research questions there is a statement about the mesosystem not being  included for ‘research method limitations’ – please explain more fully.

Author response: Thank you for your comment. Several sentences have been added: “Among these, the mesosystem is excluded from the analytical framework of the study.The reason is that the mesosystem represents the interactions and connections between different microsystems (e.g., family-school relations, peer-family interactions), which are often indirect and complex. From the perspective of individual volunteers, it is difficult to accurately observe or articulate these inter-system interactions. Therefore, to ensure the reliability and clarity of the data, this study focuses on the microsystem, exosystem, macrosystem, and chronosystem, which are more directly perceivable and reportable by participants.”

Comment 1-5: My more major concerns are methodological. If I have understood correctly the data corpus is rather small at under five hours of qualitative data.  I’m presuming participants were only interviewed once and multiple waves (section 2.2) meant recruiting and interviewing new participants?

Author response: We followed the guidance of Braun and Clarke (2006) for thematic analysis, starting with a small number of participants and then assessing whether data saturation was achieved. Additional participants were recruited only if saturation had not been reached. Although the total interview time was relatively short, each participant was interviewed for approximately 15–20 minutes, which was sufficient to generate rich qualitative data because the interview questions were focused and shared with participants in advance. This approach allowed us to collect meaningful insights while maintaining methodological rigor.

Comment 1-6: I didn’t really have a very good sense of who the participants were. The inclusion criteria of individuals who ‘sustained’ volunteering arent very clear. Did the sample include those who had withdrawn from volunteering or who had changed volunteer positions. This would be helpful to know.

Author response: In this study, the sample are university students who had participated in volunteering. This included students who were currently active in volunteering, as well as those who had previously participated or changed volunteer positions, as we aimed to capture a broad range of volunteering experiences.

Comment 1-7: The analysis is generally rather shallow and descriptive. I’d recommend reading and citing some of the many more recent papers on thematic analysis by Braun and Clarke – they have clarified and explained their approach (and different variants) if you can offer a deeper and more interpretative account of the analysis.

Author response: Thank you for the suggestion. While Braun and Clarke havSince these works primarily focus on research methodology rather than the substantive content of our study, we have cited only the article “Using Thematic Analysis in Psychology” (Braun & Clarke, 2006).

Comment 1-8: I actually feel that your approach is more in line with a qualitative content analysis. You seem to have identified and then quantified in most cases (with N and %) content units that fit with the ecological layers rather than something more inductive and thematic.I think QCA is a more plausible model. Most of the material in 3.1.1, 3.1.2, 3.1.3, 3.1.4, 3.2.1 and 3.2.2 summarises rather than analyses the data.

Author response: We thank the reviewer for the insightful comments. Our primary approach is thematic analysis, although we reported frequencies to indicate the relative prevalence of certain factors. The main reason for using thematic analysis is that it allows for a more interpretative and explanatory understanding of participants’ volunteering. If reporting frequencies and percentages is considered inappropriate, we are happy to remove these elements in a revised manuscript.

Comment 1-9: I also wasn’t sure why there were no tables of quotations for 3.3.

Author response: When exploring factors influencing volunteering within the chronosystem dimension, participants mentioned only a single factor, namely large-scale historical events experienced over a lifetime. As a result, the table for Section 3.3 would have contained only one row, which led us to initially remove it from the manuscript.

However, we agree with your point regarding the consistency of presenting findings, and therefore we have added a table in Section 3.3, as you suggested.

Comment 1-10: I also wasn’t sure why there were no tables of quotations for 3.4.

Author response: Section 3.4 presents negative cases rather than factors explaining individuals’ volunteering from the EST perspective. We believe it is important to consider the differences in how various types of findings are presented, and therefore we did not present this content in a table.

Comment 1-11: Finally, I feel the Chinese context needs explaining a bit more – to what extent to cultural and university values promote volunteering.

Author response:Thank you. We have added a paragraph to the Conclusion section:

“Besides, this study was conducted with a sample of Chinese university students, primarily due to accessibility considerations. Although the findings offer insights into factors influencing sustained volunteering participation, the results may reflect characteristics specific to the sociocultural and educational context in China. Therefore, caution should be exercised when generalizing the findings to other national or cultural settings. Future research could examine whether the identified factors operate similarly across different cultural contexts.”

Comment 1-12: A few aspects did not make sense to me. Why is attending a PhD defence considered ‘volunteering’ etc.

Author response: Thank you for pointing out the lack of clarity. We agree that the previous wording may have caused confusion. We have revised the sentence to clarify that participants were involved in volunteer services supporting such events, rather than merely attending them. The revised sentence now reads:

“In addition, some participants engaged in university- and school-based volunteer services supporting events such as graduate thesis defenses and opening ceremonies, where they were responsible for tasks including coordination and communication, venue booking and setup, and minute-taking.”

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for the opportunity to review this paper, which addresses the topic the sustainability of volunteering among university students. 

Please see below my comments on this manuscript.

Introduction and Literature Review

The authors have failed to separate the Introduction from the Literature Review. This is a major concern. The Introduction should establish the research context, define the problem statement, and highlight the research gap, whereas the Literature Review should conceptualize terms and analyze existing scholarship. By fusing these sections, the problem statement is not clear, and the justification for using the EST model is not sufficiently grounded. Therefore, I suggest the authors to reorganize the paper in order to establish a distinct theoretical and conceptual foundation before moving to the methodology. 

Methodology

The study utilizes a sample of 15 participants. While this is acceptable for thematic analysis, the authors do not explicitly state whether theoretical saturation was reached. It is essential to confirm that no new themes emerged during the final interviews to ensure the validity of the 15 identified themes.

In addition, in the abstract and methodology, the authors state that the mesosystem was excluded. Since the study explores sustained participation, the interactions between microsystems (e.g., how university demands affect family support or vice versa) are important. The authors must provide a robust theoretical justification for this omission.

Results

The identification of 15 themes across the systems is a commendable effort, and the introduction of the controllability framework is the most original contribution of this work. However, this framework should be more emphasized to categorize the "restrictive factors" mentioned in the results. Currently, the findings feel slightly descriptive; linking them more tightly to the controllability levels would enhance the analytical depth of the paper. 

Discussion

The authors should go beyond stating that their results align with previous studies. They need to explain how their findings specifically refine/challenge the EST model in the context of modern, post-pandemic student life. 

Moreover, the suggestions (e.g., ECTS credits, better communication) are somewhat generic. I recommend the authors use their controllability framework to provide specific/actionable strategies for Universities/NGOs. 

Conclusion 

The conclusions should be more concise, focusing on the core contribution of the study. Additionally, the Limitations section must address the geographical and cultural specificity of the sample, as the findings may not be directly generalizable to different socio-economic or educational systems.

Author Response

Comment 2-1: Introduction and Literature Review. The authors have failed to separate the Introduction from the Literature Review. This is a major concern. The Introduction should establish the research context, define the problem statement, and highlight the research gap, whereas the Literature Review should conceptualize terms and analyze existing scholarship. By fusing these sections, the problem statement is not clear, and the justification for using the EST model is not sufficiently grounded. Therefore, I suggest the authors to reorganize the paper in order to establish a distinct theoretical and conceptual foundation before moving to the methodology. 

Author response: You are right. However, most articles published in Behavioral Sciences combine the Introduction and Literature Review, so we followed this protocol.

Comment 2-2: Methodology. The study utilizes a sample of 15 participants. While this is acceptable for thematic analysis, the authors do not explicitly state whether theoretical saturation was reached. It is essential to confirm that no new themes emerged during the final interviews to ensure the validity of the 15 identified themes.

Author response: Thank you. One sentence has been added: “This iterative process continued until data saturation was achieved, with no new themes emerging, resulting in a three-month data collection period from June to September 2025.”

Comment 2-3: In addition, in the abstract and methodology, the authors state that the mesosystem was excluded. Since the study explores sustained participation, the interactions between microsystems (e.g., how university demands affect family support or vice versa) are important. The authors must provide a robust theoretical justification for this omission.

Author response: Thank you for the insightful comment. One paragraph has been added: “Among these, the mesosystem is excluded from the analytical framework of the study.The reason is that the mesosystem represents the interactions and connections between different microsystems (e.g., family-school relations, peer-family interactions), which are often indirect and complex. From the perspective of individual volunteers, it is difficult to accurately observe or articulate these inter-system interactions. Therefore, to ensure the reliability and clarity of the data, this study focuses on the microsystem, exosystem, macrosystem, and chronosystem, which are more directly perceivable and reportable by participants.”

Comment 2-4: Results. The identification of 15 themes across the systems is a commendable effort, and the introduction of the controllability framework is the most original contribution of this work. However, this framework should be more emphasized to categorize the "restrictive factors" mentioned in the results. Currently, the findings feel slightly descriptive; linking them more tightly to the controllability levels would enhance the analytical depth of the paper. 

Author response: This study focuses on facilitative factors driving students’ sustained volunteering, as participants primarily reported positive experiences that supported their continued engagement. Accordingly, we categorized these facilitative factors using the EST framework. Data on restrictive factors were limited, likely due to participants’ focus on what motivated rather than hindered their volunteering; we plan to examine restrictive factors in a future study. Thank you very much for your suggestion.

Comment 2-5: Discussion. The authors should go beyond stating that their results align with previous studies. They need to explain how their findings specifically refine/challenge the EST model in the context of modern, post-pandemic student life. 

Author response: We appreciate your valuable suggestion. In the revised Discussion section, we have added a detailed analysis of the similarities and differences between our findings and prior research (Holdsworth, 2010; Axlund McBride & Lott, 2015; Studer & Von Schnurbein, 2013), and how findings challenge the EST by highlighting the chronosystem’s role in shaping sustained volunteer participation among university students.

Comment 2-6: Moreover, the suggestions (e.g., ECTS credits, better communication) are somewhat generic. I recommend the authors use their controllability framework to provide specific/actionable strategies for Universities/NGOs. 

Author response: We thank the reviewer for this insightful comment. In an academic paper, the focus should primarily be on presenting empirical findings and discussing them based on actual data. Using the controllability framework to provide specific/actionable strategies for universities and NGOs is indeed a valuable direction; however, we did not design experiments or collect data for such interventions. Any recommendations beyond our findings would therefore be speculative rather than academically grounded. Therefore, we did not enlist the possible strategies based on the controllability framework.

However, the direction you suggested is indeed very promising, and we are currently planning a follow-up study in which such strategies will be explored.

Comment 2-7: Conclusion. The conclusions should be more concise, focusing on the core contribution of the study. Additionally, the Limitations section must address the geographical and cultural specificity of the sample, as the findings may not be directly generalizable to different socio-economic or educational systems.

Author response: Revision made as suggested. Thank you.

Reviewer 3 Report

Comments and Suggestions for Authors

This article is highly interesting, theoretically focused and well‑structured. It employs EST to investigate Chinese college students’ volunteering behaviors and yields sound findings. Nevertheless, the manuscript can be further improved as follows:

     1.Regarding the participants, more detailed demographic information should be provided, such as age, major, university location and grade level, to demonstrate sample diversity.

2. Were the interview questions evaluated by experts or adapted from existing research?
3. For data analysis, the inter‑rater reliability results should be reported.
4. The research implications could be more inspiring for educators. More detailed implications could be added in lines 636–667 to help universities encourage young people to engage in volunteering.
5. In the conclusion, the authors could address how the findings answer the research questions more clearly.

Author Response

Comment 3-1: This article is highly interesting, theoretically focused and wellstructured. It employs EST to investigate Chinese college students’ volunteering behaviors and yields sound findings.

Author response: Thank you very much!

Comment 3-2: Regarding the participants, more detailed demographic information should be provided, such as age, major, university location and grade level, to demonstrate sample diversity.

Author response: Thank you. Revision made as suggested: “These 15 participants were drawn from four academic disciplines: Law, Engineering, English Language and Literature, and Teaching English to Speakers of Other Languages (TESOL). Among them, 12 were female and three were male. Six participants were undergraduate students, while nine were enrolled in graduate programs. Due to ethical considerations, specific ages were not collected; however, all participants were generally within the age range of 19 to 24 years, reflecting typical university student demographics. This sample composition provided a diverse yet representative perspective across academic levels and fields.”

Comment 3-3: Were the interview questions evaluated by experts or adapted from existing research?

Author response: We apologize for not having the interview questions evaluated by experts or adapted from existing research. The main reason is that we designed the questions as indirect prompts to encourage participants to share their volunteering experiences in their own words, allowing us to extract relevant information ourselves. While this approach may generate a large amount of data that is not always directly relevant—thus posing challenges for data analysis—it minimizes reliance on predetermined questions.

Specifically, although this study aims to examine factors sustaining university students’ participation in volunteering through the lens of Ecological Systems Theory (EST), the interview protocol did not include direct questions such as “What factors at the macrosystem level influence your volunteering?” Instead, participants were invited to recount their volunteering experiences and describe what volunteering meant to them. This strategy was intended to elicit rich and authentic qualitative data. While the EST framework was not explicitly introduced during the interviews, it guided subsequent coding and analysis. Using this indirect approach allows participants’ motivations to emerge inductively rather than being constrained by predefined categories, thereby reducing potential response bias.

We appreciate your suggestion and will consider consulting experts or referencing existing research when designing interview protocols in future studies to further strengthen the rigor and validity of our qualitative instruments.

Comment 3-4: For data analysis, the interrater reliability results should be reported. 

Author response: Thank you for this important comment. In qualitative content analysis, discrepancies between coders are common, particularly during iterative coding processes in which subthemes are continuously refined and redefined. In our study, coding was conducted independently by two researchers, followed by multiple rounds of discussion to resolve disagreements and reach consensus.

Because the coding framework evolved throughout the analytic process, it was not feasible to calculate and report statistical inter-rater reliability indices (e.g., Cohen’s kappa) at each stage. We acknowledge that the absence of a formal reliability coefficient may limit methodological transparency. This will be carefully addressed in future research by incorporating more systematic procedures for reporting inter-rater agreement.

Comment 3-5: The research implications could be more inspiring for educators. More detailed implications could be added in lines 636–667 to help universities encourage young people to engage in volunteering.

Author response: Revised as suggested. See: “University administrators and volunteer coordinators can use these findings to design programs that better support students’ sustained participation by addressing factors at multiple levels and over time. Policy makers and educators can also apply these insights to create interventions that target controllable factors, making volunteer engagement more effective and sustainable.”

Comment 3-6: In the conclusion, the authors could address how the findings answer the research questions more clearly.

Author response: Revised as suggested. Thank you.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for responding to my comments. I don't feel it is appropriate to cite %s in a thematic analysis so please remove these.

Author Response

Comment: Thank you for responding to my comments. I don't feel it is appropriate to cite %s in a thematic analysis so please remove these.

Author response: Thank you for your comment. We have removed all the percentage-related data from the manuscript.

Reviewer 2 Report

Comments and Suggestions for Authors

I thank the authors for their detailed responses and for addressing the methodological concerns. I find their objective arguments regarding the paper’s structure and the scope of the recommendations acceptable. The revised manuscript is significantly strengthened.

I have only two minor suggestions for further enhancing the paper's impact:

1. To better highlight the original controllability framework, the authors might consider adding a summary table or figure mapping the 15 themes to the three controllability levels.

2. A very brief mention in the abstract of why the mesosystem was excluded (e.g., due to its indirect nature in self-reports) would provide immediate clarity to the reader.

Author Response

Comment 2-1: I thank the authors for their detailed responses and for addressing the methodological concerns. I find their objective arguments regarding the paper’s structure and the scope of the recommendations acceptable. The revised manuscript is significantly strengthened.

Author response: Thank you!

Comment 2-2: To better highlight the original controllability framework, the authors might consider adding a summary table or figure mapping the 15 themes to the three controllability levels.

Author response: We sincerely thank you for this constructive suggestion. We agree that mapping the 15 themes onto the three controllability levels in a summary table could potentially make the framework more explicit and accessible.

However, we would like to clarify that in the present study, the controllability framework is introduced primarily as a conceptual analytical lens rather than as a fully operationalized classification system. Our qualitative data were not originally collected or coded with controllability dimensions in mind. Therefore, assigning each theme definitively to one of the three controllability categories (controllable, partially controllable, minimally controllable) would require additional systematic coding procedures and validation to avoid oversimplification or subjective misclassification. Given the exploratory nature of this study and the absence of coding schemes specifically designed to assess controllability levels, we consider it methodologically inappropriate to impose a formalized categorization at this stage.

That said, we fully recognize the value of your suggestion. We are currently developing a follow-up study in which controllability will be incorporated as an explicit analytical dimension and examined through more systematic coding and validation procedures. The results of that work will be reported in a subsequent paper. We sincerely hope for your understanding regarding the scope and methodological boundaries of the present study, and we greatly appreciate your insightful recommendation.In future research, we plan to incorporate controllability as an explicit coding dimension, develop clearer operational definitions for each level, and employ inter-coder reliability checks to ensure classification rigor. Such efforts would allow for a more robust and empirically grounded validation of the framework. However, this falls beyond the scope of the present study.

Comment 2-3: A very brief mention in the abstract of why the mesosystem was excluded (e.g., due to its indirect nature in self-reports) would provide immediate clarity to the reader.

Author response: Thank you for your suggestion. A sentence has been added to the Abstract: “A thematic analysis, guided by the Ecological Systems Theory (EST), was performed, with the mesosystem excluded from the analytical framework due to its indirect and less observable nature in participants’ self-reports. ”