Assessing the Economic Energy Level of the Chengdu–Chongqing Economic Circle: An Integrative Perspective of “Field Source” and “Field”

Round 1

Reviewer 1 Report

comments as attached

Comments for author File: Comments.pdf

Author Response

RESPONSE TO REVIEWER #1

The paper is required to make the following revisions before the publication is considered.

Response: We would like to express our gratitude to you for your time and effort in reviewing our submission and furnishing constructive comments to help us improve the content and presentation of the manuscript. In this revision, we have made substantial changes throughout the manuscript as per your thoughtful suggestions. For more details, please refer to our point-to-point response to your comments.

1. The first section “Introduction” has only one paragraph. I suggest the authors to cut at the proper place to emphasize the importance and logic of the whole argument of the study. Moreover, the authors should write clearly the purposes of this study before the methodology is conducted.

Response: We thank you for your excellent suggestion. Following your advice, the revised version expands the first section“introduction”from one paragraph into four paragraphs. The logic of this section is as follows. The first paragraph proposes that it is an urgent need to heighten the economic energy level (EEL) of the Chengdu-Chongqing Economic Circle (CCEC) from the national overarching development strategy; the second paragraph elaborates the steps of improving the EEL of CCEC, which should start from the dual-core of Chengdu and Chongqing from the regional development perspective; the third paragraph clarifies the purpose and significance of this study; the last paragraph shows the structure and content of the rest of the paper. (For details of the revisions, please see the highlighted text in green in Section 1 on Page 2)

2. The “field source” and “field” are two important concepts used in this study. However, there are no specific definitions when they first time appear in the manuscript.

Response: We are thankful for your constructive advice. Following your advice, this revision has given the definitions of “field source” and “field” when they appear in this manuscript for the first time. Following their definitions in physics, we also furnish their economics meanings that are used in the context of this research. More specifically, this paper defines that “A physical field is a physical phenomenon or force effect in space. Fields and field sources coexist and depend on each other (Zeng, 2011). A "field source" is a point at the center of radiation that radiates energy outward (He et al.,2015). Field source is a relative concept. In the economics field, the field source can be a region or a city, which changes according to the geographical space under consideration.” (For details, please see the highlighted text in green in the last paragraph on Page 3).

3. The abstract should be more condensed. Now, it has too much space for the background and no objective for the study and no important results or conclusions for the study

Response: Thanks for your constructive advice. In this revised manuscript, we have thoroughly rewritten the abstract by shortening the background and emphasizing the objective and the novelty of this study. At the same time, as per your suggestion, we have added the main conclusions of this study. (For details, please see the highlighted text in the Abstract in green on Page 1).

4. At the end of Literature review, the author state that “……current research has integrated field sources into fields to assess the city energy level and the tourism energy level by exploiting their interdependence. Capitalizing on the aforesaid ideas, this paper takes an integrative perspective of internal and external urban functional energy levels. Such assessment is presumably more comprehensive and objective.” The difference between this study and the previous studies is not significant. The authors should write clearly about the deficiency of the past studies and distinct the novelty and contribution of this study.

Response: We are grateful for your excellent advice to help us improve the research value of this article. As per your recommendation, we have rewritten the concluding part of the literature review to comment on the deficiency of existing studies, thereby clarifying the novelty and contribution of this study. More specifically, we state that“However, the current research on the regional EEL solely focuses on the perspective of field source, namely single dimension of ‘internal comprehensive development level’. Based on the ‘field source’ and ‘field theory’ of interdependence, and the urgent need for the sustainable economic development of high quality, as well as the future trend of globalization with the flow space, this single-dimensional framework not only deviates from the theory, but also fails to meet the need of the reality, or adapt to the future trend. To close the gap, this paper innovatively assesses the regional EEL by accounting for two interdependent dimensions of ‘internal comprehensive development level’ and ‘external economic connection level’. (For details, please see the highlighted text in green in the third paragraph on Page 4).

5. The authors use 1160 data points on the two core cities Chongqing and Chengdu and there are 29 indicators during 2000 to 2019. But the 2 authors did not explain the distribution of the data points between these two cities. Furthermore, since the data spread in a wild rang of time period, 2000-2019 the authors explain clearly how these indicators are treated at the same the base for construction from these data.

Response: We thank you for your constructive suggestions. In this revision, Firstly, we have explained the composition of the two dimensions of “internal comprehensive development level “(PLE) and “external economic connection level “(OI), respectively. (Please see the highlighted text in green in the first two paragraphs on Page 6); Secondly, since there are 29 indicators across 20 years for the four cities, it is difficult to display the statistics of all data points, following your suggestion, we have selected two indicators (pq2, Lb3) to show the distribution of the data points for Chongqing, Chengdu, Tianjin, and Beijing during 2000 and 2019. (For details, please see the highlighted text in green and Figure 2 on Page 8); Finally, we have reported and analyzed the results of the data points. (Please see the highlighted text in green in the second paragraph on Page 8)

6. It is quite confusing that about the use of the data. The statement “this paper also collects 1160 data points of Beijing and Tianjin in the past 20 years through the aforesaid data sources to assess their economic energy levels. In total, we collect 2320 data points of these four cities.” The authors should state clearly what exactly the data are used in this study for quantitative analyses. On Page 8, there is some description about the data, “two groups of data with 60 sample data points and 80 sample data points.” It is quite confusing about the data used in this study. How come there are so many magnitudes about the data?

Response: We are grateful for your thoughtful question. It is our fault that we did not describe the data clearly enough in Section 5.1 in the original submission. This revision attempts to present the data in a more detailed manner. (Please see the highlighted text in green in the second paragraph on Page 7) In the original version, we wanted to compare the data of 60 samples (three cities: Chongqing-Chengdu-Tianjin over 20 years across the 29 indicators. We treat each city’s data in a particular year as one sample, resulting in 60 samples) with those of 80 samples (four cities: Chongqing-Chengdu-Tianjin-Beijing over 20 years across the 29 indicators, see the text in Section 5.2.2 from Page 8 to13). Presumably, the fewer samples, the harder it is to verify the rationality of the model and our empirical study confirms this point. For example, the fitting of the CFA model with 60 samples is worse than that with 80 samples in the test of the confirmatory factor analysis (CFA). Following your comment, we found that while this comparison test has incremental value to our study, it is easy to cause misunderstanding and confusion about data and the result as you rightfully pointed out. As such, we removed the discussions about 60 samples in this revised manuscript.

7. There are no definitions for all the index computed in Table 1. The readers will not be able to know what the meaning of each index.

Response: We are grateful for your thoughtful question. As per your recommendation,

 this revision has strengthened the descriptions of the criteria used to judge the reliability analysis of the Cronbach’s a and showed the meaning of the test values of 80 samples. As mentioned in our response to your Comment #6, we have deleted the discussions about 60 samples in Table 1. (For details, please see the highlighted text in green in Section 5.2.2“(1) Reliability Analysis”on Page 9)

8. On Page 10, it is said this paper uses the maximum likelihood estimation to carry out a single-factor CFA test and a first-order multi-factor CFA test of the five-in-one combination model (PLEOI) on the five dimensions of production, life, ecology, outer interaction level, and internal interaction level (P, l, E, O, I). Table 3 is not a typical way to present the estimation results, if it is, it is hard to know what the estimation coefficients are? Here is to suggest that the authors should present a standard way of maximum likelihood estimation.

Response: We are grateful for your thoughtful comments. CFA is part of a larger family of the methods known as structural equation modeling (SEM) and plays an essential role in validating models in path or structural analyses. It is true that the standard regarding what should be reported in CFA studies is of particular importance. We use the maximum likelihood estimation from the software Amos 26.0 to test the CFA. The Amos result provides 25 indicators of fitting degrees as the judgment basis. In general, we report the fitting degree index of the results by the Chi-square(χ2), GFI, CFI, and RMSEA. However, we wish to show our research results more comprehensively to attest the good fitting of our model, so we select the most frequently reported indexes as identified in the reference (Jackson and Gillaspy,2009), ranging from Chi-square(χ2) to DF, Chi-square/df, P-value, GFI, AGFI, CFI, RESEA, NFI, IFI, and TLI. To present our basis more specifically, we put the screenshots related to this part of the reference (Figure 1) below our response to your question for your information. Moreover, as mentioned earlier, we have deleted the test results for the 60 sample data points in Table 3. (For details, please see the highlighted text in green in Table 3 on Page 11)

Figure1. The screenshot for the descriptive statistics for the reported index

9. It is hard to read, see, and understand the Figure 3 and Figure 4. The authors need to present these Figures with high resolution

Response: We thank you for your valuable suggestions that help us improve the readability and presentation of the figures. As mentioned above, we dropped any discussions about the 60 sample data points to avoid confusion. So the original Figure 4 is now removed. Following your advice, we have enlarged the Figure (Please see Figure 4 on Page 13). At the same time, we have also refined Figure 3 (Figure 2 in the original version) and further explained the index value from the text in the upper left corner of Figure 3 (For details, please see the highlighted text in green in the last paragraph on Page 12)

10. The methods in this paper are quite heavy. From index construction, index validity testing, factor analysis, maximum likelihood estimation, weight determination, and fuzzy analyses. It seems the procedures explanations of each method are mixed with the outcomes. It is 3 extremely hard to understand the purpose of each method, how each method is operated, and the explanations of the outcomes from each method. It is strongly the authors to rewrite this section, this is the major section of this paper. If the readers do not understand the necessity of each method and the explanations of the outcomes from each method this big part of the section will really downgrade the contribution that the authors intend to achieve.

Response: Thank you for making this excellent point to help us improve the content and presentation quality of this article. Following your suggestion, in this revision, Starting from Section 5, we have added an overarching description sentence to briefly explain the rationale and purpose of each method to enhance readability. We have also revised the content throughout this section. (See the highlighted text in green in the first paragraph on the Page 7; the highlighted text in green in Section 5 from Page 7 to 19, respectively)

11.Because of the heavy methods involved as the previous comment indicates, this section also lacks of discussion of the results. The implications of the results are required and not just the description of the results.

Response: We would like to express our gratitude to you for your thoughtful suggestion to enhance the implications of the main results. In this revision, we have revised the contents that mix the methodology and results. To better explain the results and their implications, we have added Section 6 (Discussion) in the revised manuscript. This revision significantly expands discussions of our results and their managerial implications from both theoretical and intuitive angles (for details, please see the highlighted text in green in Section 6 from Page 20 to 22)

Other comments

1. What are the units for the vertical for Figure 5- Figure 9?

Response: We thank you for your valuable suggestions that help us improve the readability and presentation of this paper. We have added the vertical title in Figure 5- Figure 9 to reflect the EELs at the two subindicators’ and the overall level (Please see the details from Page 17 to 20)

2. On Page 7, is there any special purpose for enlarge these wordings “Corrected Item Total Correlation (CITC)? Similarly, on Page 8 for these wording “The Cronbach α Item Deleted (CAID)

Response: We thank you for your spotting these typos. This revision has corrected these enlarged texts. (Please see the highlighted text in green on the second paragraph on Page 9)

Author Response File: Author Response.pdf

Reviewer 2 Report

Introduction:

The theoretical and empirical research gap that should be identified in the introduction, has been poorly developed. Furthermore, I recommend better articulating the added value and novelty of your study. The ultimate motivation of the study needs to be enunciated more meaningfully, in order to convey a truly new message if you are to make a strong contribution. Therefore I suggest better highlighting the novelty of your research.Moreover, I could suggest also to add one sentence for the presenting the structure sections of the paper and their content which is very useful for reader.

  The literature review doesn't demonstrate an adequate understanding of the relevant literature in the field and cites an old range of literature sources, as well as existing gaps in the literature that need to be addressed and articulated more expressively. The literature review in the paper needs to be updated and solidified based on the relevant most recent research studies. More explanation is needed regarding the research design, methodology. The findings and recommendations need to be presented in greater depth. I suggest elaborating much more on the theoretical and managerial implications and their impact. In general, the citations and references need to be updated and include more recent and related works in the field for the whole sections of the manuscript. Additionally, I would also advise you to try to follow the MDPI Instructions for Authors for the Sustainability journal, https://www.mdpi.com/journal/sustainability/instructions, especially in the General consideration section where it is specifically specified about Research manuscript sections: Introduction, Materials and Methods, Results, Discussion, Conclusions (which are always at the end :) (For example: Kindly refer to Conclusion and limitation which you have included future research in it).

Good luck! Reviewer

Author Response

RESPONSE TO REVIEWER #2

1. The theoretical and empirical research gap that should be identified in the introduction, has been poorly developed. Furthermore, I recommend better articulating the added value and novelty of your study. The ultimate motivation of the study needs to be enunciated more meaningfully, in order to convey a truly new message if you are to make a strong contribution. Therefore, I suggest better highlighting the novelty of your research. Moreover, I could suggest also to add one sentence for the presenting the structure sections of the paper and their content which is very useful for reader.

Response: We would like to express our gratitude to you for your valuable suggestions. As per your suggestions, we have made significant changes throughout this revised manuscript. More specifically, firstly, we have highlighted the theoretical and empirical research gap. From the angle of reality, we state that “there still exist significant gaps, both in absolute and relative terms, in the economic energy levels (EELs) among CCEC, the Beijing-Tianjin-Hebei region, the Yangtze River Delta, and the Guangdong-Hong Kong-Macao Greater Bay Area. ”（Please see the paragraph on Page 2）and, then from the theoretical angle, the traditional evaluation of the regional economic energy level (EEL) solely considers the "internal comprehensive development level’’, which does not account for the interdependence of the “field source” and “field” theory. (For details, please see the highlighted text in green in the third paragraph on Page 2 and in the third paragraph on Page 4); Secondly, we clarify the motivation of this study as “it is an urgent need to improve the economic energy level (EEL)of the Chengdu-Chongqing Economic Circle (CCEC) and should start from the dual-core of Chengdu and Chongqing and gradually expand to the whole area as reflected by the current development status and characteristics of CCEC”. (Please see the highlighted text in green in the second paragraph on Page 2); Thirdly, we have emphasized the novelty of this study in different locations of this revised manuscript. For instance, “In contrast to the traditional evaluation of the regional economic energy level (EEL) solely from the ‘internal comprehensive development level’, this paper takes an angle on the interdependence and co-existence of ‘field source’ and ‘field’ to construct a preliminary index system that accounts for the‘ external economic connection level’ as well. "（Please see the highlighted text in green in Abstract; see the highlighted text in green in Section 1 Introduction in the third paragraph on Page 2; see the highlighted text in green in Section 2 in the third paragraph on Page 4 ）Finally, we have added the last paragraph in Section 1 to elaborate the remaining structure of the paper. (For details, please see the highlighted text in green in the last paragraph on Page 2)

2.The literature review doesn't demonstrate an adequate understanding of the relevant literature in the field and cites an old range of literature sources, as well as existing gaps in the literature that need to be addressed and articulated more expressively. The literature review in the paper needs to be updated and solidified based on the relevant most recent research studies. More explanation is needed regarding the research design, methodology. The findings and recommendations need to be presented in greater depth. I suggest elaborating much more on the theoretical and managerial implications and their impact. In general, the citations and references need to be updated and include more recent and related works in the field for the whole sections of the manuscript. Additionally, I would also advise you to try to follow the MDPI Instructions for Authors for the Sustainability journal, https://www.mdpi.com/journal/sustainability/instructions, especially in the General consideration section where it is specifically specified about Research manuscript sections: Introduction, Materials and Methods, Results, Discussion, Conclusions (which are always at the end :) (For example: Kindly refer to Conclusion and limitation which you have included future research in it).

Response: We are grateful for your excellent advice to help us improve the presentation and quality of this article. As per your recommendations, we have reviewed related literature and updated the latest relevant literature. For example, References 1-7, 16, 18, 22, to name a few. In terms of the content of this manuscript, we have clarified the research gap, emphasized the novelty of this study, and better presented our research findings. (For details, please see the highlighted text in green in Section 2 from Page 3 to 4). At the same time, we are very grateful for your suggestion to follow the MDPI’s Instructions for Authors. Following your advice, we have added a new Section 6 “Discussions” to further elaborate the managerial implications of our research results. We also rewrote Section 7 “Conclusion and Limitation” to succinctly summarize the conclusion of this research and point out future research opportunities (For details, please see the highlighted text in green in Section 6 from Page 20 to 22; see the highlighted text in green in Section 7 from Page 22, respectively)

Good luck! Reviewer

Response: We would like to express our sincere gratitude to you for your time and effort in reviewing our submission. We greatly appreciate the many thoughtful and constructive comments that you have put forward to help us significantly improve the presentation and content of this manuscript. Thank you once again!

Author Response File: Author Response.pdf

Reviewer 3 Report

the paper is intersting but i think that it's not good for this journal.

The connection with sustainability and sustainable development is not mentioned, I caa find only a mention to the ecology, but it's not important because i cannot find it in the keywords. if you like to publish in this journal these aspects must be emphasized, if it's possible.

the Hypothesis are missed

I suggest to improve the literature review. In this journal you can find several paper that can help you.

Please check the mistakes in the references, for example capital letters.

Author Response

RESPONSE TO REVIEWER #3

the paper is interesting but i think that it's not good for this journal.

Response: We are grateful for your endorsement of our research and recognition that “the paper is interesting”. And we greatly appreciate the many thoughtful and constructive comments that you have put forward to help us significantly improve the presentation and content of this manuscript. Following your recommendations, we have made substantial changes to the article as detailed in our point-to-point response to your comments below.

1. The connection with sustainability and sustainable development is not mentioned, I can find only a mention to the ecology, but it's not important because i cannot find it in the keywords. if you like to publish in this journal these aspects must be emphasized, if it's possible.

Response: Thank you for your insightful comment. We concur with you that a strong connection should be established between our research and the topic of this journal (i.e. sustainability and sustainable development). It is our fault that we did not clearly present this link in our original manuscript. In this revision, we have clarified the link between our research and the main theme of this journal. For example, in Section 1“Introduction”we stated that “This research is conducive to a scientific and reasonable evaluation of the EEL and the result helps Chengdu-Chongqing twin cities to improve their EELs for high-quality and sustainable development by following the trend of globalization.”(For details, please see the highlighted text in green in the third paragraph in Section 1 on Page 2); Next in Section 2“Literature Review”, we stated that“Jin et al. (2018) [22] argued that understanding regional economic agglomeration patterns is critical for sustainable economic development, urban planning and proper utilization of regional resources. As such, the urban energy level from the view of fields can be treated as a special kind of “ external economic connection level” and reflects a city’s interaction with other cities, which is of great significance to the sustainable development of the regional economy, the evolution of regional spatial structure and urban planning.”（For details, please see the highlighted text in green in the first paragraph in Section 2 on Page 4). In terms of the novelty of this research, we stated that “Based on the‘field source’and ‘field’ theory of interdependence, and the urgent need for the sustainable economic development of high quality, as well as the future trend of globalization with the flow space, this single-dimensional framework not only deviates from the theory, but also fails to meet the need of the reality, or adapt to the future trend.”（For details, please see the highlighted text in green in the third paragraph in Section 2 on Page 4); In Section 7 “Conclusion and Limitation”, we stated that “this paper applies the optimized model to obtain the EELs of the Chengdu-Chongqing twin cities, which helps to foster their high-quality and sustainable development under the general trend of globalization”（For details, please see the highlighted text in green in the third paragraph in Section7 on Page 22). In closing, we have established in the revised manuscript that sustainable development is critical concern in our research.

2.the Hypothesis are missed

Response: We thank you for your helpful question. Given our structural equation modeling framework, we collect data and empirically validate the model in our paper. Hypothesis testing is not concern in this type of research. The main content and idea of our study are as follows.

This paper proposes an evaluation framework for the regional EEL from the perspective of “field source” & “field”. The novelty of this research is reflected by a holistic incorporation of the internal comprehensive development level and external economic connection level. We then apply this proposed approach to assess the EELs of Chengdu and Chongqing in CCEC. The calibrated model passes the dual test of statistical and empirical validation, showing the reasonableness of the proposed regional EEL evaluation system based on “field source” & “field”. Subsequently, this paper applies the optimized model to obtain the EELs of the Chengdu-Chongqing twin cities, which helps to foster their high-quality and sustainable development under the general trend of globalization. Moreover, this research also sheds insights on how to connect the two cities to form an axis for further expansion to the surrounding areas, thereby realizing gradual radiation and overall improvement in a point-axis-plane fashion and making the CCEC the fourth growth pole in China.

3. I suggest to improve the literature review. In this journal you can find several paper that can help you.

Response: We thank you for your excellent suggestion. Following your advice, we have expanded the literature review（For details, please see the highlighted text in green in the third paragraph in Section 2 from Page 3 to Page 4). At the same time, by reviewing relevant literature of this journal, we note that some literature is closely related to our research. As such, we have cited some articles as shown below. (For details, please see the last part of References on Page 22-23).

References:

Qu, R.; Rhee, Z.; Bae, S. J.; Lee, S. H. Analysis of Industrial Diversification Level of Economic Development in Rural Areas Using Herfindahl Index and Two-Step Clustering. Sustainability. 2022, 14, 6733. https://doi.org/10.3390/su14116733

Wu, C.; Zhuo, L.; Chen, Z. Tao, H. Spatial Spillover Effect and Influencing Factors of Information Flow in Urban Agglomerations—Case Study of China Based on Baidu Search Index. Sustainability. 2021, 13,8032. https://doi.org/10.3390/su13148032

Jin, R.; Gong, J.; Deng, M.; Wan, Y.; Yang, X. A Framework for Spatiotemporal Analysis of Regional Economic Agglomeration Patterns. Sustainability. 2018, 10, 2800. https://doi.org/10.3390/su10082800

4.Please check the mistakes in the references, for example capital letters.

Response: We appreciate your carefully reviewing our manuscript and advise us of these typos. In this revision, we carefully follow the Instructions for Authors to reformat the references as per the requirement of the journal Sustainability (Please see the References on Page 22-24).

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

1.  The authors revised all the comments provided by the last review except the next minor presentation.  

2. The authors should know the writing logic. You should    define field and field sources respectively and then discuss their difference, similarity, or relationship. Thus, the statement “Fields and field sources coexist and depend on each other [1017]” is now placed in the wrong place. Since the title of this study is an integration of both field source and field it means to emphasize the importance in the introduction is essential.

Author Response

RESPONSE TO REVIEWER #1

1.The authors revised all the comments provided by the last review except the next minor presentation.  

Response: We would like to express our gratitude to you for your constructive comments during the first round of the review that help us to improve the quality and presentation of the manuscript. At the same time, we are thankful for your further thoughtful comments on enhancing the logic flows of the presentation. Please refer below to our point-to-point response to your comments for details.

2. The authors should know the writing logic. You should define field and field sources respectively and then discuss their difference, similarity, or relationship. Thus, the statement “Fields and field sources coexist and depend on each other [1017]” is now placed in the wrong place. Since the title of this study is an integration of both field source and field it means to emphasize the importance in the introduction is essential.

Response: We would like to express our gratitude to you for your thoughtful suggestion on improving the logic flows of our presentation regarding the key concepts of field and field source. We are especially grateful for your specific suggestions on how to proceed from here. Following your advice, we first define the key concepts of a field and field source respectively, then we discuss their relationship, followed by their economic implications in the context of our research. More specifically, we state that “A field is a physical phenomenon or force effect in space [17], such as the electromagnetic field and the gravity field. According to the principle of electromagnetic induction revealed by British physicist Faraday: electricity and magnetism exist in the form of spatial fields that are distributions of certain forces. A "field source" is a point at the center that radiates energy outward. [18]. Neither a field nor field source can exist alone. Without a field source, there does not exist a field in a certain space; If there is a field in the space, there must be a corresponding field source. When an object (a field source) exists in the space, it will generate forces (field) at each point around it. As such, a field and field source coexist and depend on each other [17]. These two concepts have been applied to the regional economics research to examine the interaction of a region and its surrounding area. The field source in this context can be a region or a city, which changes according to the geographical space under consideration. Similarly, the field in this case refers to the interaction between regions or cities.  Regions or cities and the interaction between them coexist and depend on each other.” (For details, please see the highlighted text in blue on the last paragraph on Page 3 to the first paragraph on Page 4)

Author Response File: Author Response.docx

Reviewer 3 Report

The paper is improved.

if you cannot use hypothesis, you can add the assumpions and clear exaplin them with maybe numbers 1, 2, ..... divided the literature review for the assumpion and also riconsider them in the conclusions.

Author Response

RESPONSE TO REVIEWER #3

The paper is improved.

Response: We appreciate your recognition of our effort in revising this manuscript and are grateful to you for your constructive comments during the first round of the review that help us to improve its quality and presentation.

if you cannot use hypothesis, you can add the assumpions and clear exaplin them with maybe numbers 1, 2, ..... divided the literature review for the assumpion and also riconsider them in the conclusions.

Response: We are thankful for your further constructive comments on explicitly elaborating the assumptions of this research. Following your advice, this revision explicitly elaborates the three assumptions in this research in Section 4.1 Design Principles and Assumptions of the Regional EEL Index. After reviewing relevant literature from abroad and at home, this paper makes three assumptions when we construct the index system (For details, please see the highlighted text in blue on the last two paragraphs on Page 5 and the first three paragraphs on Page 6 and, then, we have reconsidered them in Sections 5, 6 and 7)

More specifically, we state in Section 4.1 (pages 5 and 6) that “The construction of a proper index system should follow the principles of comprehensiveness, scientificity, and data reliability and availability. Based on these principles, after reviewing relevant literature from abroad and at home, this paper makes three assumptions when we construct the index system:①Based on the “field source” and “field” theory of interdependence and co-existence, this paper assumes that it will be more scientific to evaluate the EEL from the two dimensions of "internal comprehensive development level" and "external economic connection level" than traditional evaluation methods. If the EEL is assessed from the traditional single dimension of “internal comprehensive development level” such as only from the perspective of the production level, it tends to lead to misestimation.②In assessing the internal comprehensive level, this paper assumes that the holistic evaluation from the perspectives of production, life, and ecological levels is more comprehensive and systematic, which is conducive to identifying the specific problems existing in the sustainable and high-quality development of the regional economy. ③ When assessing the external economic connection level, due to data availability and quantifiability, this article assumes that the interaction between information flow and technology flow in the “flow space” is mainly attached to goods and personnel. As such, the level of external economic connection is assessed from the material, personnel, and capital flows.”

In resonance with Assumption 1, towards the end of Section 5 (page 20), we state that “Our empirical study reveals that if the traditional index system is adopted to evaluate the regional EEL, misleading comparative results might be obtained. For instance, while Tianjin as a national advanced manufacturing research and development base generally scores quite high under the traditional evaluation index system. However, when other factors are considered, Tianjin’s position drops owing to its weak performance in external and internal interactions as well as ecological levels.”(Please see the text in blue in the third paragraph on Page 20) ,“if only P is considered or the EEL is evaluated purely from the traditional production level, misleading estimations of EELs may be resulted as this approach tends to overestimate old industrial bases with traditional manufacturing-oriented industries such as Tianjin and Chongqing.”(Please see the text in blue in the fourth paragraph on Page 21) and “By comparing our evaluation with the traditional assessment, we note that the EEL tends to be misestimated if comprehensive factors about the "external economic connection level" are not taken into account” (Please see Section 7 Conclusion and Limitation on Page 22).

To resonate Assumption 2, we state that “From Figures 6, 7, and 8, we note that the Chengdu-Chongqing twin cities perform similarly in terms of P in 2019, but Chongqing significantly underperforms Chengdu once PLE is incorporated into the evaluation. This difference indicates that the sustainable and high-quality development of Chongqing's economy relies on improving the two aspects of L and E.” (Please see the highlighted text in blue in the first paragraph on Page 20), “In the meantime, it tends to underestimate the roles of life levels (L) and ecological levels (E), motivating us to propose our holistic evaluation framework in this research. Moreover, from the perspective of high-quality and sustainable development of regional economy, Tianjin and Chongqing need to focus on improving L and E.” (Please see the text in blue in the fourth paragraph on Page 21) and “at the same time, if the ‘internal comprehensive development level’ does not consider the life levels and ecological levels, we will not be able to properly identify the obstacles to the sustainable and high-quality development of regional economy along these two dimensions.” (Please see Section 7 Conclusion and Limitation on Page 22).

In terms of Assumption 3, we recognize in Section 7 that “This paper only considers the flow of personnel, goods, and capital, under the underlying assumption that the information and technology flows are attached to personnel and goods flows. However, this assumption has certain limitations, especially in the current 5G communication technology and post pandemic era, which greatly affect the flow of personnel. In addition, information flow has become a significant dimension that deserves special consideration in measuring OI. As such, a worthy future work is to further expand our framework by explicitly accounting for information and technology flows.” (Please see the highlighted text in blue in Section 7 in the last paragraph on Page 22)

Author Response File: Author Response.docx

Round 3

Reviewer 3 Report

thank you for adding the assumption in the answer, they are very clear and explicative.

I expected to find them in a clear way in the paper, assumpiton 1 ,2 and 3

I recommned to add Assumpion 1: ..... Assumption 2: ......

consider my last suggestion if you think that can improve the readeability of the paper.

Author Response

RESPONSE TO REVIEWER #3

thank you for adding the assumption in the answer, they are very clear and explicative.

Response: We are grateful to the reviewer for your constructive comments during the first two rounds of the review and are pleased that you recognized that “they are very clear and explicative” about adding part of the assumptions.  

I expected to find them in a clear way in the paper, assumpiton 1 ,2 and 3

I recommned to add Assumpion 1: ..... Assumption 2: ......

consider my last suggestion if you think that can improve the readeability of the paper.

Response: Many thanks to the reviewer for this suggestion. We have added Assumption1, Assumption2, and Assumtion3 to improve the readability of this revision. (For details, please see the highlighted text in red on the first three paragraphs on Page 6)

Author Response File: Author Response.docx