The Efficiency of Economic Growth for Sustainable Development—A Grey System Theory Approach in the Eurozone and Other European Countries

Round 1

Reviewer 1 Report

The topic of the manuscript is relevant, and its content may be of interest to potential readers. I believe that the results obtained by the authors are important.

At the same time, I have certain doubts and comments regarding some aspects of the research carried out by the authors:

1. In my opinion, the main focus should be on the relevance of the research topic, its purpose and tasks in the Introduction. Instead, the authors provide quite a lot of other information in the Introduction. Perhaps it is worth moving this material (in particular, the tables) to the beginning of the "Research results" section? I leave this question to the discretion of the authors.

2. In the last paragraph of the introduction, it is advisable to present the structure of the manuscript more clearly. It is advisable to start this paragraph as follows: "Further material is divided into several parts. Thus, in Section 2……. Section 3 presents……".

3. In the "Literature review" section, it would be worthwhile to describe in more detail the methods and indicators of evaluating the efficiency of economic growth for sustainable development existing in modern literature.

4. I recommend the authors to provide an interpretation of the concept of the efficiency of economic growth for sustainable development. What exactly do the authors mean by such efficiency? The authors also sometimes use the concept of the efficiency of transforming inputs related to economic growth into outcomes for sustainable development.

5. It would also be worthwhile to explain more clearly why exactly the indicators listed in lines 321-327 were chosen (that is, why exactly Goal 9 was chosen?).

6. If the section is entitled "Materials and Methods", then it is worth first describing the research materials (that is, input information, methods of its collection, sources of information, etc.).

7. The description of the research methodology presented in lines 207-304, in some places, in my opinion, is not completely clear and complete. In particular, how is the level of significance of various indicators taken into account? What kind of decision making are we talking about? The economic meaning of indicator (8) and the relationship between equation (13) and equation (11) are also not entirely clear. I do not question the author's models, but I think they should be explained more clearly.

8. From the empirical results obtained by the authors, it remains unclear what causes such differences between the values of the SEI-EG indicator for different countries (table 8). In particular, why are these values the highest in Bulgaria and Estonia?

9. In the Conclusions, it would be worthwhile to discuss the obtained research results in more detail and describe their practical significance.

10. I ask the authors to check the text of the manuscript for typos and errors. In particular, two sections have the same numbers (2).

I think it is appropriate to acquaint the authors with these comments, suggestions and questions. I hope that such an acquaintance helps to improve the quality of the manuscript, which is expected to be published in such a high-ranking journal as "Sustainability".

Grammar could be improved. Individual sentences can be formulated better.

Author Response

Dear Reviewer,

Thank you very much for your substantive review, which will undoubtedly contribute to a significant improvement in the quality of our publication. Below, we are sending a list of corrections we have made in response to your comments. 

1. As suggested by the reviewer, part of the material from the "Introduction" section has been moved to the "Research results" section.
2. The fragment indicating the structure of the article, as pointed out by the reviewer, has been added in the last paragraph of the introduction.
3. The literature review has been expanded to describe in greater detail the methods and indicators for assessing economic growth efficiency for sustainable development presented in contemporary literature.
4. In line with the reviewer's suggestion, the concept of economic growth efficiency for sustainable development has been clarified further.
5. The decision to utilize indicators from Goal 9 has been explained as per the reviewer's suggestion.
6. The "Materials and methods" chapter has been supplemented with a description of the input information, methods of their collection, and sources of information, in accordance with the reviewer's indications.
7. The description of the research methodology has been corrected following the reviewer's comments.
8. A broader interpretation of the research findings in relation to the countries indicated by the reviewer has been provided.
9. The Conclusions in the article have been corrected as per the reviewer's comments.
10. The numbering of the various sections of the article has been corrected, and the text has been checked for editorial and linguistic accuracy.

Should you have any doubts, we remain at your disposal.

Reviewer 2 Report

The abstract should be substantially revised. It has to emphasize the originality of your work, presenting the applied methodologies and results.

In the Introduction section the authors are writing about the Paris Agreement and the SDGs.  There is a statement: “All these circumstances have influenced the economic situation of the 56 European Union countries …” It is little bit unclear how they are connected to the economic situation. Please, clarify it.

The article is not well-structured. The paragraphs are too long, difficult to follow it. Please, split further the paragraphs.

Table1-2: They do not show the Maastricht indicators, but some selected Maastricht indicators. Please, revise the titles.

The Introduction section has too many data and analysis. I highly recommend moving them to the Results section. However, the short description of the article sections, the research question and/or hypothesis are missing. Please, add these. Please, also make the main aims of the study clear.

The Literature section presents a detailed description of the effects of the two global crises, plus the SDGs. However, the connection is blur. Please, demonstrate the link between these extremely distant topics. Another problem, that the study applies the theory of grey systems. However, I (I guess it is the case for most researchers) am not familiar with it. Please, present the theory here.

I am not sure about the ’Synthetic Efficiency Indicator for Economic Growth’. Is it a new indicator? Please, present it.

The Data subsection is completely missing, e.g. applied data, data sources, unit, etc.

The applied SEI-EG indicators are not well supported. How did you select them? On the other hand, there is no connection with the literature review. Did you carry out any statistical test (multicollinearity, etc) to check on them? If yes, please, describe it.

The main conclusion is that: “countries not belonging to the eurozone exhibited higher 407 efficiency for sustainable development as measured by the SEI-EG indicator during the 408 studied period.” I am wondering how you can make any conclusion based on the SEI-EG about sustainable development? The selected indicators are also not connected to any theories of the sustainable development.

Summary: The study in this current form is very mosaic. The literature review does not really connect to the selected indicators, theory of grey systems or the applied indicator. The research aims should be clearly described. The Conclusion section is completely missing. Please, present the importance of your results, also describing how we can use it in practice. Policy recommendations can also go here.  

Author Response

Dear Reviewer,

Thank you very much for your substantive review, which will undoubtedly contribute to a significant improvement in the quality of our publication. Below, we are sending a list of corrections we have made in response to your comments.

1. In line with the reviewer's suggestions, the originality of the work, the methods applied, and the key results have been highlighted in the abstract.
2. The impact of the Paris Agreements and SDGs on the economic situation of EU countries has been explained.
3. Paragraphs have been further divided according to the reviewer's suggestion.
4. The titles of Table 1 and Table 2 have been corrected as indicated by the reviewer.
5. Following the reviewer's comment, data and analyses from "Introduction" have been moved to "Research results". Additionally, the structure of the article sections and research questions have been described, and the main goals of the study have been defined.
6. The relationship between global crises and SDGs has been explained in more detail. In the "Literature review" section, a description of grey system theory has been added.
7. In response to the reviewer's question, we clarify that the SEI-EG indicator is an original indicator developed by the authors of the article (this is also described in the article itself).
8. The "Materials and methods" chapter has been supplemented with a description of the input information, methods of their collection, and sources of information, as indicated by the reviewer.
9. The choice of indicators within the SEI-EG has been justified in accordance with the reviewer's comments.
10. The efficiency of transforming inputs related to economic growth into sustainable development outcomes, as understood by the authors, has been explained, along with the limitations of the SEI-EG indicator and its area of applicability.
11. Following the reviewer's comments, the significance of our findings has been presented more broadly, and an explanation of how they can be used in practice (along with policy recommendations) has been provided.

Should you have any doubts, we remain at your disposal.

Round 2

Reviewer 1 Report

In my opinion, the text of the manuscript has improved. The authors took into account most of my comments. At the same time, the text of the manuscript still has certain shortcomings (mostly of a technical nature) and some debatable points, namely:

1. I do not recommend starting the Introduction with the sentence "The article's scope encompasses several themes...". The introduction should begin with a justification of the topicality of the topic, and only then proceed to a brief description of the article (purpose, main results, structure, etc.). I leave this question to the discretion of the authors.

2. All abbreviations in the text of the manuscript should be deciphered after the first mention. Please check. In particular, the abbreviation SEI-EG should be decoded in line 50. The abbreviation in the list of keywords after the abstract is also not decoded.

3. It is necessary to check the presence and eliminate the duplication of individual fragments of the text. In particular, the beginning of the paragraph, which is located in lines 265-274, partially coincides with the beginning of the paragraph, which is located in lines 505-519. Perhaps it is better to justify the choice of Goal 9 only once.

4. The manuscript does not contain a "Discussion" section. On the other hand, the authors provided a sufficiently detailed discussion of the research results in section 4. Therefore, I propose to call this section "Research results and their discussion".

5. The design of the manuscript still needs some improvement. In particular, it would be good to provide not only website links but also the names of the relevant sources in the source list.

Author Response

Thank you very much for the article review. We have corrected all issues pointed out in points 1-4 of the review. The literature description in relation to sources from the internet has been done in accordance with the Journal's editorial requirements. At the same time, we commit to making any necessary changes indicated by the article's editor.

Reviewer 2 Report

The requested changes were made. The article is ready for publishing.

Author Response

Thank you very much for the review