Activity Duration under the COVID-19 Pandemic: A Comparative Analysis among Different Urbanized Areas Using a Hazard-Based Duration Model
Round 1
Reviewer 1 Report
Now I have the chance to review this paper about activity duration under the COVID-19 pandemic. I saw some potential on it while this paper still needs substantial improvement.
1. The Introduction part and Literature Review seem a bit out of date. I noticed that all the references are only updated until 2021. However, there have been important publications related to the topic in 2022 and 2023. I do believe this paper have made some contribution, but the sentence such as “However, little research addressed the change of activity duration and their influencing factors in the context of the COVID-19 pandemic.” is correct but still there are quite a few articles regarding both the COVID-19 and the time (duration) change of activity. I agree with your stated contribution but it would be good to mention previous studies which are highly relevant.
2. Page 2 Line 64-65, “The latter has its own unique feature because the built environment under the pandemic can only be used with restrictions.” This expression may not be appropriate. Do you mean some service facilities were restricted under the pandemic?
3. I think your research indeed fills a research gap, but the significance of doing so requires further discussion in Introduction. To be specific, I mean why we should research the spatial and social heterogeneity of the change of the activity duration? Is there any policy implication or practical application value?
4. Again, this literature review may not be comprehensive enough, as there are several important and highly-relevant articles that are missing. For example, Liu and Zhang (2023) also discuss the spatial and social heterogeneity effects of the COVID-19 and related policies. Zhang and Li (2023) discuss the change of park visit during the COVID-19 and its spatial and social heterogeneity. Here are some references as examples. Please re-do the literature review to properly refer to all the relevant previous studies.
Liu, C., Zhang, W., 2023. Social and spatial heterogeneities in COVID-19 impacts on individual's metro use: A big-data driven causality inference. Applied Geography 102947.
Zhang, W., Li, J., 2023. A quasi-experimental analysis on the causal effects of COVID-19 on urban park visits: The role of park features and the surrounding built environment, Urban Forestry & Urban Greening 127898.
Park, et al., 2022. A double jeopardy: COVID-19 impacts on the travel behavior and community living of people with disabilities. Transportation Research Part A: Policy and Practice 24-35.
Li, L., Li, X., Niu, N., et al., 2023. Uneven impacts of COVID-19 on residents' utilization of urban parks: A case study of Guangzhou, China. Applied Geography 153: 102905.
Zhang, W., Ning, K., 2023. Spatiotemporal heterogeneities in the causal effects of mobility intervention policies during the COVID-19 outbreak: A spatially interrupted time-series (SITS) analysis. Annals of the American Association of Geographers 1-23.
5. 5. I believe that the main value of this article is not in its methodological innovation, making section 2.3 of literature review a bit redundant and unfocused. Instead, it should focus on methods in the literature which are relevant to this topic, at least under the background of COVID-19 pandemic, and then establish the advantages and contrivutions of the methods used in this paper.
6. Page 6 Line 258-261 give me some misleading information. I think the author should differentiate between "trip" and "activity" more clearly, as trip time and activity time are two distinct concepts. So when you mention “average duration per trip”, I guess you mean the “activity time” as described in Table 1. Please check throughout the entire Section 3 if there are still any ambiguous expressions like this.
7. I can perceive that using this method has some advantages, but I need a clearer explanation of the specific advantages of this method compared to others, especially in the context of this research and topic.
8. Page 21. Table 4. Abbreviations for variables should be introduced in the variable description section, rather than in the note under Table 4.
9. I suggest reformatting Figure 2, so that two subfigures are presented in one row for easier reading.
10. Again, in Page 22 Line 648-650. I don’t think this paper discuss the change of travel behavior because all the variables focuses on the activity time. The author should review and differentiate concepts throughout the article.
11. It seems that the author found some interesting in the results. It is a pity that the conclusions is poor. Page 23 Line 660-664, what do you mean “…. are far from the aim of COVID-19 countermeasures to reduce human mobility”? Actually, I think this statement is very subjective and vague, and cannot be directly inferred from the results in the paper. The context lacks logical connection.
As this paper has mentioned social and spatial heterogeneity, I believe it would be appropriate to further discuss spatial and social vulnerability and the role of land use policy in mediating residents’ activities during the COVID-19 pandemic.
12. Page 23 Line 665-675, this paragraph is merely a restatement of the results, and should be reorganized in a helicopter way.
There are no major issues with the English expression.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
For section “2. LITERATURE REVIEW”,
(1) In line 124, "a negligible infection risk" is mentioned, but it's not clear what this refers to. A definition or clearer explanation would be helpful here.
(2) Lines 177-184: The explanation of multiple discrete-continuous structures (MDC) is concise. It would be beneficial to provide more context on what the MDC model is and how it has been used previously in studying activity duration before discussing its applications and improvements.
(3) Line 185: “The statement about MDC models being typically used for stated preference data rather than revealed preference data” could use more explanation. Why is this the case? What implications does this have for your study?
(4) Lines 186-195: The discussion on fuzzy set theory and the hybrid probability distribution model is well laid out. However, ensure to relate these theories back to your study. Why are these theories relevant, and how do they inform your methodology?
(5) Line 192: The term "membership functions" is used without explanation. Consider defining it for readers unfamiliar with this term.
For section “3. DATA AND STUDY AREA”,
(6) Lines 279-288: The explanation for including neighborhood characteristics is good. More detailed information about the facilities-distance variables would be beneficial - how are they calculated? What types of facilities are included?
For section “4. METHODOLOGIES”,
(7) Lines 303-305: The tables are well organized. It could be beneficial to specify the measurement units for the variables.
(8) In line 386, there seems to be a reference error ("Error! Reference source not found"). Please check your referencing system and correct it.
For section “5. RESULTS”,
(9) Line 461: please make sure the number of each figure is correct. It seems like it should be “Fig. 3 Survival functions estimation for different activities and urbanized areas” instead of “Fig. 1 Survival functions estimation for different activities and urbanized areas”.
(10) Lines 410-416: You might want to explicitly state the factors that are driving the unique behavior of shopping activity durations in highly urbanized and non-urbanized areas. It would be nice if you can explain why the shopping activity duration drops more remarkably in highly urbanized areas under 75 minutes but the opposite in periods over 125 minutes.
(11) Line 423-426: It might be beneficial to discuss why the fall in the survival function values for social-related activities is more pronounced in less urbanized areas. Do less urbanized areas lack certain amenities or social hubs that cause this? This could be further analyzed.
(12) Lines 439-444: You notice an S-shaped survival function for work activities, where the reduction rate is relatively high in periods under 2.5 hours and between periods 7.5 hours and 12 hours. It might be interesting to delve deeper into why this pattern exists. Are there certain workplace practices or cultural norms contributing to this pattern?
(13) Lines 448-452: Your conclusion that people in urban areas tend to work longer due to pressure from the competitive environment is quite strong. However, it would be important to provide evidence that supports this claim. For instance, this could come in the form of survey data on working hours and perceived work pressure, or from studies examining the relationship between urbanization and work-life balance.
(14) Lines 483-491: While the findings on age are interesting, it might be helpful to include more about how different age groups’ behaviors changed before and during the pandemic. This will provide more context to the reader and could also help substantiate the findings.
(15) Lines 502-510: When discussing the influence of having a valid driver's license and owning a car on activity durations, it could be interesting to also take into account the location of these households. Are these households in urban, suburban, or rural areas? This could possibly influence both the need for a car and the opportunities for hiking.
(16) Lines 592-601: When referring to lower-level land-use variables, be more explicit about what these variables are.
(17) Line 594: Consider rewriting this sentence to clarify the relationships between retail and hospitality areas, shopping choices, and the duration of shopping activities. It seems contradictory as it stands; you might mean "more available shopping choices negatively affect the duration of shopping activities" instead.
(18) Lines 602-608: Make sure to discuss why highly and moderately urbanized areas tend to have longer shopping durations. Is it related to the proximity and accessibility of shops? Is it related to socio-economic factors?
(19) Lines 622-625: It's not entirely clear why a facemask requirement would impact activity durations in this context. Perhaps you could provide some additional detail on why this might be the case.
No comments. Reasonably well written.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
I am satisfied with authors' reply to my comment.
