PONE-D-25-16590Impact of Circadian Rhythm Preference on Performance in China's Standardized Residency Training: The Mediating Role of LonelinessPLOS ONE

Dear Dr. Yang,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

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The reviewer raised a number of questions and points to address. I would expect that you respond to each of these. It is particularly important to provide sufficient detail regarding the statistical methods used and potential issues with confounding variables multiple testing correction. The interpretation of the data should mention the relationship between evening chronotypes and light exposure from artificial sources as well as sleep deprivation and a possible impact of loneliness on study time.  In addition, it may be worth considering whether extensive studying in front of a computer screen at night could induce an evening chronotype as well as increase the risk of loneliness.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: This is an interesting and potentially valuable investigation of the relationship of circadian rhythm preference (chronotype), loneliness, and academic performance in Chinese medical residents undergoing standardized training. The findings have the potential to inform interventions and support programs in order to improve the well-being and academic success of residents undergoing standardized training. I believe this work can be recommended, however, there are several crucial issue that have to be addressed first:

1. Considering the increasing prevalence of smartphone use and its potential impact on circadian rhythms via blue light exposure, did you investigate whether differences in smartphone usage patterns or evening light exposure among your participants might have influenced the observed relationship between chronotype, loneliness, and academic performance?

2. The study found that evening chronotype residents achieved higher final grades, a contrast to findings in adolescents. To better understand these differing outcomes, did the authors consider the potential influence of differences in study time or learning strategies employed by residents with evening chronotypes? Furthermore, given that adolescents with evening chronotypes often experience chronic sleep restriction due to early school start times, did the authors explore whether a similar sleep debt and associated daytime impairments might contribute to the lower academic performance typically observed in this population? As sleep duration was not assessed in this study, lack of such crucial information has to be discussed as limitation.

3. The study proposes that loneliness mediates the relationship between chronotype and academic success. However, is it possible that loneliness, in and of itself, primarily serves as a factor enabling increased study time, thereby indirectly contributing to higher grades? Could this alternative explanation, where loneliness facilitates longer study hours, influence the interpretation of the observed mediating role?

4. Methods sections and specifically statistics requires improvements. Considering the limited detail provided regarding normality testing, model selection for the generalized linear model, and potential confounding variables in the mediation analysis, could the authors provide a more explicit description of these methodological aspects to enhance the rigor and transparency of their findings? Additionally, given the number of statistical tests performed, did the authors consider adjustments for multiple comparisons, and if not, how might this impact the interpretation of the reported results?

5. Considering that age is known to influence both chronotype and loneliness, I was wondering if the authors could comment on whether they assessed age as a potential confounding or moderating variable in their study? Any insights into the role of age in these relationships would be very helpful.

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Reviewer #1: No

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Impact of Circadian Rhythm Preference on Performance in China's Standardized Residency Training: The Mediating Role of Loneliness

PONE-D-25-16590R1

Dear Dr. Yang,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Herman Wijnen, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: I thank the authors for adequate answers to my questions. I have no further questions at the moment.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy .

Reviewer #1: No

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