PONE-D-24-45297What role do adolescents’ independent food purchasing choices play in their dietary quality?PLOS ONE

Dear Dr. Shaw,

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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Academic Editor

PLOS ONE

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Additional Editor Comments:

Methodology

The authors should indicate which of the variables were normally distributed and which ones were not. It will also be helpful in the variables section for the authors to indicate how the variables were categorized. For example, readers are lost as to how the diet quality finally used in the analysis.

In table 5, it will be good to include the standard errors because the confidence intervals are quite wide. With a sample of size of 80 and some missing participants, the authors should include a section about their regression diagnostics.

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Reviewers' comments:

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Reviewer #1: Partly

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

Reviewer #1: No

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Reviewer #1: No

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Reviewer #1: Yes

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5. Review Comments to the Author

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Reviewer #1: This study reports the results of study using ecological momentary assessment to measure indoendent food purchases among adolescents and assesses the association with dietary quality via FFQ. A strength is the use of EMA methods, however the convenience sample is very small and I have doubts about the suitability of the sample for many of the analyses presented and some of the analytic approach.

The introduction and discussion are mostly well written and well referenced. Perhaps the discussion is a little on the long side and could be trimmed down using more concise language.

Methods -

Line 48 - how were ppts recruited from these locations? Posters, email lists, announcements etc?

Line 64 "where possible, member of research team..." may be useful to report as a %of total sample how many times research team were present

Photographs were submitted for 23% of food entries, and photos / receipts were used to assess accuracy. What were the results of this checking process (ie how many of those photographs matched the ppts description of the food item?) Is there any other evidence to support that the participants were able to accurately and reliably categorise food items purchased?

Given the feasibility / acceptability results have not been published elsewhere, could the authors briefly summarise here? (Even if there are plans to publish this in future, a very high level summary would be useful)

The healthiness score tallied scores of -1 and 1 for non-adhering and adhering foods respectively. And then foods that could not be categorised were coded as 0 and included in this overall score. This approach essentially treats items of unknown "healthiness" as being halfway between the known values of -1 and 1. However, the more accurate treatment of these foods would be to code them as missing and not include them in the overall score. For example, a combination food "sandwich" might in reality fall in the "adhering" category. But defaulting to categorise it as "0" will pull the overall score downwards artificially. The opposite for a sandwich that would be accurately coded as "not adhering". I suggest the authors conduct the analyses coding these items as "missing" and present this as a sensitivity analysis, at the very least, otherwise replace analyses with the score recalculated treating uncategorised food as missing.

Line 151 - I'm not familiar with the term "test for trend" or how it retains statistical power (which test is this one replacing due to small numbers?)

Results-

What was the justification for the sample size recruited? Was an a priori power calculation conducted? Rationale is needed. In particular, I'm doubtful that the N provides sufficient power for the interaction test (maybe on the low side to address aim 1, even). Further, statistical testing of many of the subgroup differences presented in table 4 is not appropriate given the very small sample size. Further, in text, these results are described and statements about purchasing being "higher" in one group compared to another are based on comparison of the raw numbers. Despite p values being reported (which I don't think is appropriate for many of the presented analyses), they don't appear to have been used as a criterion for determining where differences lie. I'd suggest being very clear in the text that these comparisons are not supported by statistical tests due to small numbers within subgroups.

Given the study used a convenience sample, what was the rationale behind presenting adjusted analysis (including demographics that were unequally distributed across levels of the key outcome and exposure variables) as sensitivity analyses? It seems that failing to control for these variables is not optimal treatment of the data. I would encourage authors to present adjusted analyses as the primary analyses, and then report the unadjusted analyses as sensitivity analyses.

In tables and figures presenting healthfulness scores, it would be useful to specify as a reminder that scores closer to 1 indicate a healthier score, and closer to -1 indicate less healthy. This will assist readers viewing these elements out of context.

Line 228 "this relationship remained when.." this is a bit confusing given there was no significant relationship in the first place, suggest amending text to "there was also no significant relationship between x and y when..."

The conventional criteria for statistical significance is p less than .05, not equal to .05. Please amend the text in the results at line 232, Abstract, and Discussion accordingly.

The information presented in Figure 2 would be easily conveyed in text, so I would suggest deleting this figure for brevity.

I wasn't sure whether the results reported in text and in figure 3 were based on regression analyses adjusting for all other covariates or not. Please ensure this is clear- either way, from the methods it sounds as though both adjusted and unadjusted were run, but at present only one set of analyses are reported in the results.

Discussion

Line 372 "because of uncertainty regarding who made no recordings" - I'm struggling to grasp what this sentence means - I note that the following sentence provides further detail, but I'd suggest replacing them both with the following wording or similar: "...because it could not be determined whether participants who did not record any purchases did so because they did not make any independent food purchases or because they did not adhere to the study protocol"?

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Reviewer #1: No

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PONE-D-24-45297R1What role do adolescents’ independent food purchasing choices play in their dietary quality?PLOS ONE

Dear Dr. Shaw,

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.

 Please address the comments I have raised in the attached file. 

Please submit your revised manuscript by Aug 11 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Sandra Boatemaa Kushitor, Ph.D.

Academic Editor

PLOS ONE

Journal Requirements:

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Additional Editor Comments:

Dear Authors,

Congratulations for revising the manuscript. The current format of the manuscript is well done, however the discussions and implications are not supported by the findings. I have made suggestions for you in the attached file for you to consider.

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While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

Attachments

Attachment

Submitted filename: Adolescent purchases vs diet_PLOS_Response_May25_2_Clean.docx

The association between adolescents’ independent food purchasing and dietary quality differs by socioeconomic status: findings from a pilot study

PONE-D-24-45297R2

Dear Dr. Shaw,

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Kind regards,

Sandra Boatemaa Kushitor, Ph.D.

Academic Editor

PLOS ONE

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