Dear Dr. Siguenza,

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PLOS ONE

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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?

Reviewer #1: Partly

Reviewer #2: Partly

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

Reviewer #1: Yes

Reviewer #2: Yes

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

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

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

Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1:  I had the pleasure of participating in the review process of a manuscript entitled "Factorial Structure, Validity, and Sex Differences of the UCLA-R 2 Loneliness Scale in Ecuadorian Adolescents."

The present manuscript, like any scientific paper, is subject to improvement, and I request the authors to make necessary corrections before acceptance for publication.

General comments:

The manuscript aimed to validate the UCLA-R 2 Loneliness Scale in Ecuadorian adolescents by assessing its factor structure, validity and gender invariance.

The introduction is well written and structured, providing the necessary literature review in relation to the study objective.

The methods are clear and relevant.

The discussion supports the results and conclusions.

Specific comments:

- Title: in my humble opinion, it should be better if you use “Gender Invariance” instead of “sex differences”. If you are ok, please change the expression throughout the manuscript.

- Abstract:

• Typos: “objective” instead of “objetive”.

• The objective should provide more information about the different analyses assessed to validate the scale.

• The method is too short and doesn't contain enough information, try enriching it with the necessary and appropriate information (e.g., average age and standard deviation, socio-demographic variables, sample proportions for conducting the EFA and CFA...).

• Results: provide findings from the EFA.

- Introduction:

• As I mentioned earlier, the introduction is clear and well structured. However, I recommend that the authors add a paragraph about the need for cross-cultural validation. Why is it important to use a validated scale in the local language?

- Materials and methods:

• Procedure:

- I must admit that the use of online surveys has several limitations (depending on the study). So, my question is: how did you try to limit respondent bias? Did you use a guide for using online surveys (e.g., CHERRIES (Eysenbach, 2012)? If not, try to explain your own procedure.

• Results:

- I suggest deleting table 2, since you've included the necessary information in the text, otherwise it'll be a repetition.

- Please provide findings related to the normality of the distribution assessed in table 3 by Skewness and Kurtosis and add it to table’s title.

• Discussion:

- I recommend adding paragraphs on practical and theoretical implications of the study.

• Limitations:

- Several other limitations should be added such as the bias on the use of online surveys, or the limited sample size.

- Explain why you didn’t conduct convergent or divergent validity.

• Conclusion:

- - I'm requesting that you rewrite the section, as you've just reported the results. The conclusion should be limited to an answer to the main objective of the study, so it's not necessary to report the GFI results.

Reviewer #2:  First, the method and results section of the scale adaptation study is very detailed and well presented. However, although the study was conducted in a large sample, it is an adaptation study and I am not sure that it meets the journal's requirement in this direction. My comments for the authors are as follows:

In line 20, I think the sentence means that the bifactor model does not change between genders in terms of measurement invariance. It could be written a little more clearly.

In line 102-103, Can you give some brief information about this methodology, is it like a simple random sampling method?

In line 216-217, Explanations can be given as to why this item does not load on any factor.

In table 5, Calculating alpha reliability for each dimension and calculating the stratified alpha coefficient for the entire scale may be more accurate in providing the lower limit of alpha reliability for multidimensional scales.

In line 274, You can point out with reference that it is more accurate to look at the difference between these indices, as the chi-squared statistic is affected by sample size.

In line 338, It was stated that one item was removed because it did not load sufficiently on any of the factors. It would have been good to explain why this item did not work with adolescents. Has a similar situation occurred with the same item in other adaptation studies?

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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.

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Reviewer #1: Yes:  Amayra Tannoubi

Reviewer #2: No

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Factorial structure, validity, and gender invariance of the UCLA-R Loneliness Scale in Ecuadorian adolescents

PONE-D-25-08122R1

Dear Dr. Siguenza,

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,

Ted C.T. Fong, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

Reviewer #1: All comments have been addressed

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

Reviewer #1: Yes

**********

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

Reviewer #1: Yes

**********

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

The PLOS Data policy

Reviewer #1: Yes

**********

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

Reviewer #1: Yes

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Reviewer #1: After the first round of revision, I thank the authors for their rigorous work yo improve the quality of the manuscript. The paper is now suitable for publication. Congrats!!

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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: Yes:  Amayra Tannoubi

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