Geographic Variations in Human Mobility Patterns during the First Six Months of the COVID-19 Pandemic in California

Round 1

Reviewer 1 Report

Dear Authors,

thank you for this interesting paper to review. There are some suggestions of mine how to improve the paper:

1. In the introduction, I would add an aspect of changes in medical services during the pandemic, also in dnetistry, see the examples of the articles:

- Plaza- Ruíz SP, Barbosa-Liz DM, Agudelo-Suárez AA. Impact of COVID-19 on the future career plans of dentists. Dent Med Probl. 2022;59(2):155–165. doi:10.17219/dmp/143548

- Flores-Quispe BM, Ruiz-Reyes RA, León-Manco RA, Agudelo-Suárez A. Preventive measures for COVID-19 among dental students and dentists during the mandatory social isolation in Latin America and the Caribbean in 2020. Dent Med Probl. 2022;59(1):5–11. doi:10.17219/dmp/142033

- Lewandowska M, Partyka M, Romanowska P, Saczuk K, Lukomska-Szymanska MM. Impact of the COVID-19 pandemic on the dental service: A narrative review. Dent Med Probl. 2021;58(4):539–544. doi:10.17219/dmp/137758

2. I would also refer it to the working in the direct contact with patient and saliva being a reservoir of the virus - please refer to it as to a method of diagnostics of COVID, eg.:

- Duś-Ilnicka I, Krala E, Cholewińska P, Radwan-Oczko M. The Use of Saliva as a Biosample in the Light of COVID-19. Diagnostics (Basel). 2021 Sep 26;11(10):1769. doi: 10.3390/diagnostics11101769.

3. Lines 133-148 -> when desctibing the methods.. please, add the information if this is not against the law, please state there if you had any permissions for "position tracking" and if so - please, use the special assignment

4. I would use a graph to visualize materials and methodology 

5. Is it possible tu use less pixels on fig. 2 (same S6-8)? 

6. In the discussion, please add the aspect why do the authors think the mobility changed (although it might seem obvious)

7. Limitations should be at the end and should be a separate chapter.

8. You should also add in the discussion the possibilities of repetition of this survey - also would it be possible to check the exact same group? Could it be used for other type of research? 

I rate this article as an interesting one, although it needs some improvements. Best regards- A.P.S.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

line 136, reference is made to a 'table A' not present in the document

line 143, what is CBG?

in general, the description of the methodology is very complex and difficult to interpret, we recommend the use of infographics and flowcharts for its description and a reorganisation and simplification of this part, which is crucial for judging the overall quality of the research

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

The study investigated the human mobility patterns at CBG level proxied by 5 selected human mobility indicators and discovered 2 iconic HMPs and their top important social determinants (either positively or negatively). The article “Geographic variations in human mobility patterns during the 2 first six months of the COVID-19 pandemic in California” is good but requires improvements in writing and discussion.

 Below are the comments and suggestions:

·       Include some important results in the Abstract.

·       There is NO conclusion section in the article.

·       The citation numbering is incorrect, see line 32, it starts with 4. Check all.

·       The authors used “we” more than 60 times in the article. Change the sentence structure to reduce it and improve the writing.

·       Line numbers 105,106, rephrase like these sentences…”We would like to address and solve this asynchronous pattern issue by using DTW-SOM, because we want the HMPs to have small tolerance on time shifting”

·       Clarify the 4 HMP groups.

·       Are the below your observations or referring to literature (7) or else? Line 107-110  

For example, some places might be faster in responses to the shelter-in-place orders by few days than others, but if their HMPs are similar in shape, we would assume these places were having similar compliance with orders. We noted that different human mobility variables may present unique and even contrasting characteristics.

·       Line 136 refers (Table A)… where is that table?

·       Many sentences are unnecessary very long. Proofread the entire article and re-write such sentences.

·       Correct the below information in lines 421-422:

The ANOVA test results reported in Table 1 demonstrated that the group means of all 17 SED variables are significantly different across the mobility groups for each of the human mobility indicators. Full descriptions of the SED variables’ abbreviations could be found in Table 3.

·       Write and refer to the exact numbering … see line 251...(Figure 1 and Supplementary Figures 1-4). And line 478 (Figures 2 and Supplementary Figure 5-8)… Supplementary should be S5-S8 etc.

·       Improve the quality of Figure 3.

·       Figure S8 is overlapped on the text; correct that.

·       There is a need to differentiate/highlight clearly the significance and novelty of the study.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 4 Report

The study is well designed and devoted to an important issue of human mobility patterns in pandemic conditions and during lockdown. Its outcome would be of great significance during future pandemics. Thus, the paper should be published, although some minor improvements of its structure and discussion section are suggested below.

The merits

I have no comments on the statistical methods employed in the study and found that they are appropriate and used properly. However, I have some suggestions that could potentially improve the discussion section:

Line 362 - You point out here the differences between rural and urban areas. It is possible that these differences stem not from differences in social mobility groups and from socioeconomic and demographic variables, but rather from the distance to local urban centres? I am not familiar with the study area, but, for example, in some European countries, the differences in human behaviour between rural and urban areas were partly correlated with the distance to the local city centre (inhabitants of more remote areas spent less time at home during lockdown because they simply spent more time in commuting. Are you sure that the variation can be explained solely by demographic factors?

Lines 377-389 - Here you identify geographic regions in which the increases in median home dwelling time were moderate. You explain that the population of these regions could be less aware of the pandemic situation. However, I do not see such a straightforward correlation of home-dwelling time with awareness of the situation. Once again, I don't know how the shelter-in-place order worked in California, but some countries of the European Union urger residents to limit social contacts and comply to the social distancing rules, but without giving a clear shelter-in-place order. This, of course, also led to an imminent peak in home dwelling time, but those who did not limit their travel times do not necessarily underestimated the situation. In Poland, for example, a peak of activity was observed in rural areas and in public parks, because it is relatively easy to maintain the social distance there. Thus, there was no clear correlation between the stay-at-home pattern and awareness of pandemics. Do you think that in your data set the mobility time that is not related to full-time and part-time work behaviour can be explained by lower compliance with social distancing orders, or are there some alternative scenarios? I am of course aware that it is not possible to find out the reason why an individual left his home using the data that you have, but it could be a point that could be elaborated on in the discussion.

Structure

The manuscript features a significant amount of data and introduces many acronyms and abbreviations. Therefore, I would suggest applying some minor changes to the structure to improve its comprehension among the readers:

Lines 225-264 - These two paragraphs belong to the Results chapter. However, when you take a closer look at them, you will notice that no direct outcome of the study is shown there. In fact, both paragraphs discuss the volumes of data analysed, the study time, and introduce abbreviations for cluster centres. Consider moving these two paragraphs to the Methods section.

Lines 350-353 - These two sentences include percentages that were already shown in Figure 1. Consider removing them, because they generate redundancy and overwhelm a reader with numbers that you provide in a more friendly way.

Lines 407-412 - Are you sure that this sentence should be placed directly in the text, as a separate paragraph? For me, it looks like this is part of the caption of Figure 3, truncated and placed in the text.

Editing issues

Although as a non-native I cannot comment on the quality of the language, there are some minor editing issues that should be fixed:

Line 73 - Use "SafeGraph" instead of "SafeGragh".

Line 423 - Description of SED variables is in Table 1, not in Table 3.

Line 433 - The results of LDA analysis are shown in Table 3, not in Table 2.

Author Response

Please see the attachment,

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Dear Authors,

thank you for applying all changes. I would like you to add just two more information:

1. In the materials and methodology - please, add why did you chose California for analysis, if you had more states included in the study

2. in limitations - the devices might have stayed at home while a person left home / office etc.

Thank you

Author Response

Point 1. In the materials and methodology - please, add why did you chose California for analysis, if you had more states included in the study.

Response 1. We added the reason of choosing Califronia as our study area in this pilot study.

Point 2. in limitations - the devices might have stayed at home while a person left home / office etc.

Response 2. We added the suggested limitation in our discussions.

Thank you for your time and expertise. We are grateful for the opportunity to work with you as such a knowledgeable and dedicated reviewer.

Reviewer 2 Report

no other modifications are necessary 

Author Response

Your expertise and attention to details of our manuscript were greatly appreciated, and I am confident that the end result will be stronger because of your contributions. I also appreciated your prompt response time and the constructive feedback you provided, which allowed us to make the necessary revisions in a timely manner.

Reviewer 3 Report

The authors have incorporated the changes.

Author Response

Your insightful comments and suggestions have been incredibly helpful in improving the overall quality of our work. Many thanks and best regards!