The Impact of Urban Education on the Income Gap of Urban Residents: Evidence from Central China

Round 1

Reviewer 1 Report

1. The manuscript falls within the “Sustainability” journal’s aims and scope
2. A clear aim(s) of the paper (study) and/ or hypothesis(es) have not been established
3. Up to me, the paper in its Introduction provides insufficient justification for the importance of the topic. How does this study contribute to existing knowledge (and not only in China)? Why the questions and issues addressed in the Introduction are interesting and important for theory and practice? Why do they need to be addressed? How does China differ from other countries in respect to the addressed topic?
4. The paper lacks any theoretical grounding (no theory).
5. Literature Review: I think that showing that other scholars have previously explored the relationship between education and the income gap is not enough. Literature selection is heavily biased towards China-related publications. The paper failed to cite highly relevant studies (e.g. Becker, G. S., Chiswick, B. R. (1966). Education and the Distribution of Earnings. The American Economic Review, 56(1/2), 358–369.;  Becker. G.S. Human Capital: A Theoretical and Empirical Analysis, with Special Reference to Education). A similar remark relates to the relevant journals (e.g. The Journal of Economic Inequality),
6. Methods: What was the period of the analysis? How many urban regions (provinces, cities) were included in the analysis?
7. Results/discussion: 170-171: “From Table 3, we can see that when the urban education level in Central China increased by 1%, the Gini coefficient of urban income decreased by 0.065%”. Should it be: increased by 1 percentage point rather than by 1%, and decreased by 0.065 percentage points? The same remark applies to the other interpretations of the results. What about the discussion of control variables (Table 3)? What about confronting own results with those of other scholars who focus on China? Are the current results similar to or different from findings of other studies, if differed, why?
8. Spelling and punctuation, e.g. “In contract, for urban middle-income, middle and upper-income, and high- income groups,property income and net operating income account for a relatively high proportion of their income groups” (lines 177-179)’ “the Central china’s urban” (line 181),
9. Statistical data on China (the Introduction section) lacks sources. No references for China Statistical sources except for information they were applied (Yearbook, social and economic statistics yearbook of China's counties and cities, provincial statistical yearbooks, urban statistical yearbook) lines 130-133.
10. The manuscript starts with the statement that it “empirically analyses the impact of urban education level and its different levels on the income gap of urban residents in Central China” as well as “provides suggestions for the formulation of scientific and reasonable urban education development policies in Central China. I suggest rephrasing the first part (“education level and its different levels”)
11. As the manuscript is submitted to is the international journal I propose to present values not only in national currency (39321 RMB) but also in USD or EUR

Author Response

1. The manuscript falls within the “Sustainability” journal’s aims and scope
2. A clear aim(s) of the paper (study) and/ or hypothesis(es) have not been established

In response to the reviewer’s comment, we revised the abstract and introduction in lines 14-17, 53-66 as follows: Through investigating the impact of urban education level and its different levels on income gap of urban residents in the central China，this paper provides the basis for formulating scientific and rational urban education development policies in Central China.  So what impact does urban education have on the income gap of urban residents in Central China (the urban education refers to schooling and training that take place in large, densely populated areas with diverse populations)? Does urban education expand the income gap of urban residents or narrow the income gap of urban residents in Central China? Urban education comprises three different levels: urban primary education, urban secondary education and urban higher education. Does each specific level of urban education expand the income gap of urban residents or narrow the income gap of urban residents in Central China? To narrow the income gap while improving the income level of urban residents in Central China, which level of urban education should be developed? To address these questions, this paper empirically analyzes the impact of urban education level and its different levels on the income gap of urban residents in Central China, and provides suggestions for the formulation of scientific and reasonable urban education development policies to narrow the income gap of urban residents in Central China.

3. Up to me, the paper in its Introduction provides insufficient justification for the importance of the topic. How does this study contribute to existing knowledge (and not only in China)? Why the questions and issues addressed in the Introduction are interesting and important for theory and practice? Why do they need to be addressed? How does China differ from other countries in respect to the addressed topic?

In response to the reviewer’s comment, we revised the introduction in lines 67-73 as follows: This study helps to enrich the theory of educational economics and improve the research content of income distribution theory. It provides a new empirical basis for improving the income level of urban residents and narrowing the income gap of urban residents in Central China. As the income gap of urban residents has also widened in some other developing countries (Naito and Nishida, 2017; Marcella, 2021)[1,2], this study also provides a reference for other developing countries similar to the Central China to develop which level of urban education to narrow the income gap of urban residents.

4. The paper lacks any theoretical grounding (no theory).

In response to the reviewer’s comment, we revised the literature review in lines 75-83, 126-130 as follows: There have been many systematic studies on the relationship between education level and income distribution, such as Schultz's human capital theory, Becker's human capital theory and Mincer's human capital theory, all aiming to explain the wage gap according to the different amounts of worker's capital accumulated through formal education and training. Mincer (1958), Schultz (1961), Becker and Chiswick (1966), Becker (1993), Mussida and Picchio (2014) confirm the existence of a positive correlation between education and income, and that the gap in the level of formal education widens the personal income gap. Therefore, in order to narrow the income gap, the key point is to increase investment in formal education [3-7]. It is quite conceivable that the education level and its different levels can affect the income gap by improving the quality and skills of workers (quality and skill effect), promoting occupation conversion of workers (occupation conversion effect), improving labor productivity (productivity effect), and boosting labor mobility and transfer (labor flow effect), and so on.

5. Literature Review: I think that showing that other scholars have previously explored the relationship between education and the income gap is not enough. Literature selection is heavily biased towards China-related publications. The paper failed to cite highly relevant studies (e.g. Becker, G. S., Chiswick, B. R. (1966). Education and the Distribution of Earnings. The American Economic Review, 56(1/2), 358–369.;  Becker. G.S. Human Capital: A Theoretical and Empirical Analysis, with Special Reference to Education). A similar remark relates to the relevant journals (e.g. The Journal of Economic Inequality),

In response to the reviewer’s comment, we revised the literature review in lines 75-83, 92-98, 104-105, 107-109, 113-116, 119-120, 126-130 as follows: There have been many systematic studies on the relationship between education level and income distribution, such as Schultz's human capital theory, Becker's human capital theory and Mincer's human capital theory, all aiming to explain the wage gap according to the different amounts of worker's capital accumulated through formal education and training. Mincer (1958), Schultz (1961), Becker and Chiswick (1966), Becker (1993), Mussida and Picchio (2014) confirm the existence of a positive correlation between education and income, and that the gap in the level of formal education widens the personal income gap. Therefore, in order to narrow the income gap, the key point is to increase investment in formal education [3-7]. Most studies have shown that a more equal distribution of education contributes significantly to reducing income inequality, and that educational expansion is a major factor in reducing educational inequality and thus income inequality (Battistón and Gasparini, 2014; Khan et al., 2015; Celikay and Sengur, 2016; Hall, 2018; Qazi et al., 2018; Shahabadi et al.; 2018; Coady and Dizioli, 2018; Arshed, et al., 2018; Lee and Lee, 2018; Arshed, et al., 2019; Panori and Psycharis, 2019; Alxandersen et al.; 2021) [20-31].  These studies found that there are significant differences in the impact of higher education on the urban-rural income gap in different regions. They pointed out that improvement of compulsory education and vocational education level helps to narrow the urban-rural income gap.  Some studies showed that the improvement of rural education level does not necessarily reduce rural income inequality, but a more equal distribution of rural education contributes significantly to reducing rural income gap.  There are also some studies that focused on the impact of urban education level on income gap of urban residents, most of which have shown that urban education is a major factor in reducing income gap of urban residents. It is quite conceivable that the education level and its different levels can affect the income gap by improving the quality and skills of workers (quality and skill effect), promoting occupation conversion of workers (occupation conversion effect), improving labor productivity (productivity effect), and boosting labor mobility and transfer (labor flow effect), and so on.

6. Methods: What was the period of the analysis? How many urban regions (provinces, cities) were included in the analysis?

In response to the reviewer’s comment, we revised the introduction and model construction in lines 44-45, 147-148 as follows: Since the reform and opening up, Central China has significantly improved urban educational level (the study covers 6 provinces in Central China, including Shanxi, Anhui, Jiangxi, Henan, Hubei, and Hunan), with average educational attainment reaching 10.25 years in 2020; Among them, i and t represent the i cities (the sample cities are 141) and the year (the sample period is 1998-2019), respectively.

7. Results/discussion: 170-171: “From Table 3, we can see that when the urban education level in Central China increased by 1%, the Gini coefficient of urban income decreased by 0.065%”. Should it be: increased by 1 percentage point rather than by 1%, and decreased by 0.065 percentage points? The same remark applies to the other interpretations of the results. What about the discussion of control variables (Table 3)? What about confronting own results with those of other scholars who focus on China? Are the current results similar to or different from findings of other studies, if differed, why?

In response to the reviewer’s comment, we revised the results and discussion in lines 227-228, 259-261, 288-290, 317-319, 372-374, 397-405, 353-364 and 230-231 as follows: From Table 3, we can see that when the urban education level in Central China increased by 1 percentage point, the Gini coefficient of urban income decreased by 0.065 percentage point, which was significant at the 10% level. This indicates that the improvement of urban education level in Central China is conducive to narrowing the income gap of urban residents. This result is similar to the findings of Tian and Zhou (2017), Wang and Deng (2020), Chen and Huang (2021) [52-53,55].  Finally, Table 3 shows that urbanization level, mobility investment of urban residents, per capita GDP and financial development level increased the Gini coefficient of urban income, although the estimated coefficients of mobility investment of urban residents and financial development level are not significant. The results indicate that improvement of urbanization level and per capita GDP widened the income gap of urban residents, while improvement of mobility investment of urban residents and financial development level have not significantly widened the income gap of urban residents. Table 3 also shows that improvement of health investment of urban residents, minimum wage standard and industrial structure help to narrow the income gap of urban residents.

8. Spelling and punctuation, e.g. “In contract, for urban middle-income, middle and upper-income, and high- income groups,property income and net operating income account for a relatively high proportion of their income groups” (lines 177-179)’ “the Central china’s urban” (line 181),

In response to the reviewer’s comment, we revised the results and discussion in lines 237-243 as follows: In contrast, for urban middle-income, middle and upper-income, and high-income groups, property income and net operating income account for a relatively high proportion of their income groups. As for why urban education can significantly increase per capita wage income, it may be that the Central China's urban residents have adequate education level, the skill level and high labor productivity enabling them to obtain information and change to higher paying jobs.  

9. Statistical data on China (the Introduction section) lacks sources. No references for China Statistical sources except for information they were applied (Yearbook, social and economic statistics yearbook of China's counties and cities, provincial statistical yearbooks, urban statistical yearbook) lines 130-133.

In response to the reviewer’s comment, we revised the introduction in lines 49, 53. For example, data source: China Statistical Yearbook.

10. The manuscript starts with the statement that it “empirically analyses the impact of urban education level and its different levels on the income gap of urban residents in Central China” as well as “provides suggestions for the formulation of scientific and reasonable urban education development policies in Central China. I suggest rephrasing the first part (“education level and its different levels”)

In response to the reviewer’s comment, we revised the introduction in lines 54-66 as follows: So what impact does urban education have on the income gap of urban residents in Central China (the urban education refers to schooling and training that take place in large, densely populated areas with diverse populations)? Does urban education expand the income gap of urban residents or narrow the income gap of urban residents in Central China? Urban education comprises three different levels: urban primary education, urban secondary education and urban higher education. Does each specific level of urban education expand the income gap of urban residents or narrow the income gap of urban residents in Central China? To narrow the income gap while improving the income level of urban residents in Central China, which level of urban education should be developed? To address these questions, this paper empirically analyzes the impact of urban education level and its different levels on the income gap of urban residents in Central China, and provides suggestions for the formulation of scientific and reasonable urban education development policies to narrow the income gap of urban residents in Central China.

11. As the manuscript is submitted to is the international journal I propose to present values not only in national currency (39321 RMB) but also in USD or EUR

As suggested by the reviewer, we have made revisions in lines 48-49 as follows: In 2020, the per capita disposable income of urban residents reached $ 5701, an increase of 8.24% from 2019 (data source: China Statistical Yearbook).

Reviewer 2 Report

Title: The Impact of Urban Education on the Income Gap of Urban 2 Residents: Evidence from Central China

The topic is important. However this work needs serious improvement before it can be reached to a publishable standard. Language is a great concern and this doesn’t meet an academic standard.

Abstract is not organised well. Your need to allocate one ow two sentences for each issue namely purpose, method, findings, discussions and conclusion. Information provided in the abstract is not quite convincing.

Introduction has failed to explore research problem and scope of the current research. I suggest the author should develop sub-topics under introduction that make clear on research problem, scope, aim and objectives along with research question. The should need to consult some recent works to identify the scope of the research. For example:

• Do Urbanized Socioeconomic Background or Education Programs Support Engineers for Further Advancement?               
• What makes a difference for Further Advancement of Engineers: Socioeconomic Background or Education Programs?

Literature review is not conceiving at al. The author have failed to provide the concept of urban education.   Urban studies refer to an education program that concentrates on theory, principle and practice related to urban development. Meanwhile, the concept of urban education refers to a method of schooling that takes place in large, densely populated areas with diverse populations. This distinction is important and the author has failed to grap it. Please consult some important journals such education and urban society, urban education review. I am not conceived with the review of urban education concept.

This model and method used in this paper has some obvious limitation and it is important to acknowledge such limitation. Robustness Test sub-section should be the part of method not the findings.

Both the theoretical and practical implications are missing.  This paper needs to undergo professional proofreading.

This needs revision and resubmit   

           

Author Response

1、The topic is important. However this work needs serious improvement before it can be reached to a publishable standard. Language is a great concern and this doesn’t meet an academic standard.

As suggested by the reviewer, we revised the introduction and other sections.

2、Abstract is not organised well. Your need to allocate one ow two sentences for each issue namely purpose, method, findings, discussions and conclusion. Information provided in the abstract is not quite convincing.

As suggested by the reviewer, we revised the abstract in lines 13-40 as follows:  It is very important for a country's sustainable economic and social development to reduce the income gap between urban residents. Through investigating the impact of urban education level and its different levels on income gap of urban residents in the central China，this paper provides the basis for formulating scientific and rational urban education development policies in Central China. Based on Central China's urban dynamic panel data, this paper examines the impact by using the system GMM (Generalized Method of Moments). The results show that overall, the improvement of urban education level helps to narrow the income gap of urban residents in Central China cities. Specifically, improvement of primary education level and secondary education level helps to narrow the income gap of urban residents, and improvement of higher education level enlarges the income gap of urban residents. Nonetheless, with further development of higher education in the cities, the income structure of lower-middle income and low-income groups will be optimized, and subsequently higher education in cities will probably narrow the income gap between urban residents. In terms of the type of cities, improvement of education level in provincial capitals widens the income gap of urban residents, and improvement of education level in prefecture level cities and county level cities helps to narrow the income gap of urban residents. For all the three types of cities, improvement of primary education level helps to narrow the income gap of urban residents, and the improvement of higher education level widens the income gap of urban residents. The improvement of secondary education level widens the income gap of urban residents in provincial capital cities, but reduce the income gap of residents in prefecture level cities and county level cities. The policy implication from this study is that to effectively and expeditiously narrow the income gap of urban residents in Central China, prefecture level and county level cities need to vigorously develop urban education, especially urban primary education and secondary education．At the same time, cities in Central China also need to actively develop higher education, although the income gap of urban residents might be widened temporarily in the short term, the development of urban higher education will increase property income and net operating income of the local middle-low income and low-income groups in the long term. Ultimately this policy would optimize the income structure of local urban residents and narrow the income gap of urban residents.

3、Introduction has failed to explore research problem and scope of the current research. I suggest the author should develop sub-topics under introduction that make clear on research problem, scope, aim and objectives along with research question. The should need to consult some recent works to identify the scope of the research. For example:

• Do Urbanized Socioeconomic Background or Education Programs Support Engineers for Further Advancement?               
• What makes a difference for Further Advancement of Engineers: Socioeconomic Background or Education Programs?

In response to the reviewer’s comment, we revised the introduction in lines 44-73 as follows: Since the reform and opening up, Central China has significantly improved urban educational level (the study covers 6 provinces in Central China, including Shanxi, Anhui, Jiangxi, Henan, Hubei, and Hunan), with average educational attainment reaching 10.25 years in 2020. At the same time, the income of urban residents in Central China grew rapidly. In 2020, the per capita disposable income of urban residents reached $ 5701, an increase of 8.24% from 2019 (data source: China Statistical Yearbook). However, the income gap of urban residents in Central China is still large. In 2020, the income disparity ratio of the total income of high-income group plus the middle and upper-income group to that of lower-middle income group plus the low-income group is about 2.71 (data source: China Statistical Yearbook). So what impact does urban education have on the income gap of urban residents in Central China (the urban education refers to schooling and training that take place in large, densely populated areas with diverse populations)? Does urban education expand the income gap of urban residents or narrow the income gap of urban residents in Central China? Urban education comprises three different levels: urban primary education, urban secondary education and urban higher education. Does each specific level of urban education expand the income gap of urban residents or narrow the income gap of urban residents in Central China? To narrow the income gap while improving the income level of urban residents in Central China, which level of urban education should be developed? To address these questions, this paper empirically analyzes the impact of urban education level and its different levels on the income gap of urban residents in Central China, and provides suggestions for the formulation of scientific and reasonable urban education development policies to narrow the income gap of urban residents in Central China. This study helps to enrich the theory of educational economics and improve the research content of income distribution theory. It provides a new empirical basis for improving the income level of urban residents and narrowing the income gap of urban residents in Central China. As the income gap of urban residents has also widened in some other developing countries (Naito and Nishida, 2017; Marcella, 2021)[1,2], this study also provides a reference for other developing countries similar to the Central China to develop which level of urban education to narrow the income gap of urban residents.

4、Literature review is not conceiving at al. The author have failed to provide the concept of urban education.   Urban studies refer to an education program that concentrates on theory, principle and practice related to urban development. Meanwhile, the concept of urban education refers to a method of schooling that takes place in large, densely populated areas with diverse populations. This distinction is important and the author has failed to grap it. Please consult some important journals such education and urban society, urban education review. I am not conceived with the review of urban education concept.

In response to the reviewer’s comment, we revised the literature review in lines 75-83, 92-98, 104-105, 107-109, 113-116, 119-120, 126-130 as follows: There have been many systematic studies on the relationship between education level and income distribution, such as Schultz's human capital theory, Becker's human capital theory and Mincer's human capital theory, all aiming to explain the wage gap according to the different amounts of worker's capital accumulated through formal education and training. Mincer (1958), Schultz (1961), Becker and Chiswick (1966), Becker (1993), Mussida and Picchio (2014) confirm the existence of a positive correlation between education and income, and that the gap in the level of formal education widens the personal income gap. Therefore, in order to narrow the income gap, the key point is to increase investment in formal education [3-7]. Most studies have shown that a more equal distribution of education contributes significantly to reducing income inequality, and that educational expansion is a major factor in reducing educational inequality and thus income inequality (Battistón and Gasparini, 2014; Khan et al., 2015; Celikay and Sengur, 2016; Hall, 2018; Qazi et al., 2018; Shahabadi et al.; 2018; Coady and Dizioli, 2018; Arshed, et al., 2018; Lee and Lee, 2018; Arshed, et al., 2019; Panori and Psycharis, 2019; Alxandersen et al.; 2021) [20-31]. These studies found that there are significant differences in the impact of higher education on the urban-rural income gap in different regions. They pointed out that improvement of compulsory education and vocational education level helps to narrow the urban-rural income gap.  Some studies showed that the improvement of rural education level does not necessarily reduce rural income inequality, but a more equal distribution of rural education contributes significantly to reducing rural income gap.  There are also some studies that focused on the impact of urban education level on income gap of urban residents, most of which have shown that urban education is a major factor in reducing income gap of urban residents. It is quite conceivable that the education level and its different levels can affect the income gap by improving the quality and skills of workers (quality and skill effect), promoting occupation conversion of workers (occupation conversion effect), improving labor productivity (productivity effect), and boosting labor mobility and transfer (labor flow effect), and so on.

 

5、This model and method used in this paper has some obvious limitation and it is important to acknowledge such limitation. Robustness Test sub-section should be the part of method not the findings.

 In response to the reviewer’s comment, we revised the methods, results and discussion in lines 147-148, 201-211, 353-364, 437-440 as follows:  Among them, i and t represent the i cities (the sample cities are 141) and the year (the sample period is 1998-2019), respectively; In order to test the reliability of the regression results, the robustness test is carried out by re measuring the dependent variable; Finally, Table 3 shows that urbanization level, mobility investment of urban residents, per capita GDP and financial development level increased the Gini coefficient of urban income, although the estimated coefficients of mobility investment of urban residents and financial development level are not significant. The results indicate that improvement of urbanization level and per capita GDP widened the income gap of urban residents, while improvement of mobility investment of urban residents and financial development level have not significantly widened the income gap of urban residents. Table 3 also shows that improvement of health investment of urban residents, minimum wage standard and industrial structure help to narrow the income gap of urban residents.

Table 5. Results of robustness test (1).

	Urban Education Level	Urban Primary Education Level	Urban Secondary Education Level	Urban Higher Education Level
C	3.214**（0.045）	2.903*（0.081）	3.116（0.123）	2.287**（0.039）
lnCst-1	0.228（0.117）	0.249*（0.062）	0.217*（0.064）	0.241（0.126）
lnCe1/lnCe2/lnCe3/lnCe4	-0.067*（0.053）	-0.035**（0.040）	-0.071*（0.059）	0.033**（0.048）
control variable	Yes	Yes	Yes	Yes
Wald test	1071.367	903.642	995.796	944.493
Sargan test	0.239	0.211	0.226	0.218
Arellano-Bond AR（1）	0.005	0.004	0.005	0.005
Arellano-Bond AR（2）	0.242	0.209	0.213	0.211

Note: ^*, ^** and ^*** indicate that the variable is significant at the level of 10%, 5% and 1% respectively.

Table 6. Results of robustness test (2).

	Provincial Capital Cities				Prefecture Level Cities				County Level Cities
	Urban Education Level	Urban Primary Education Level	Urban Secondary Education Level	Urban Higher Education Level	Urban Education Level	Urban Primary Education Level	Urban Secondary Education Level	Urban Higher Education Level	Urban Education Level	Urban Primary Education Level	Urban Secondary Education Level	Urban Higher Education Level
C	2.632*	2.620**	1.946*	3.817	4.194	2.881**	3.335*	3.927*	2.916	2.419*	2.657**	2.794
lnCst-1	0.226*	0.221*	0.237*	0.278*	0.228**	0.240	0.297*	0.224**	0.232**	0.284*	0.241	0.253**
lnCe1	0.021**				-0.059**				-0.081*
lnCe2		-0.013**				-0.039*				-0.046**
lnCe3			0.029**				-0.074**				-0.082**
lnCe4				0.022*				0.038*				0.041**
control variable	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Wald test	1022.084	853.038	930.073	882.156	662.102	916.780	867.258	834.879	903.647	943.188	795.812	973.162
Sargan test	0.228	0.199	0.211	0.204	0.155	0.213	0.201	0.183	0.210	0.213	0.175	0.218
Arellano-Bond AR（1）	0.005	0.004	0.005	0.005	0.003	0.005	0.004	0.003	0.005	0.005	0.003	0.005
Arellano-Bond AR（2）	0.212	0.193	0.199	0.197	0.151	0.202	0.195	0.171	0.198	0.201	0.164	0.205

Note: ^*, ^** and ^*** indicate that the variable is significant at the level of 10%, 5% and 1% respectively.

 

 

6、Both the theoretical and practical implications are missing.  This paper needs to undergo professional proofreading.

In response to the reviewer’s comment, we revised the introduction and literature review in lines 67-73, 75-83,126-130 as follows: This study helps to enrich the theory of educational economics and improve the research content of income distribution theory. It provides a new empirical basis for improving the income level of urban residents and narrowing the income gap of urban residents in Central China. As the income gap of urban residents has also widened in some other developing countries (Naito and Nishida, 2017; Marcella, 2021)[1,2], this study also provides a reference for other developing countries similar to the Central China to develop which level of urban education to narrow the income gap of urban residents. There have been many systematic studies on the relationship between education level and income distribution, such as Schultz's human capital theory, Becker's human capital theory and Mincer's human capital theory, all aiming to explain the wage gap according to the different amounts of worker's capital accumulated through formal education and training. Mincer (1958), Schultz (1961), Becker and Chiswick (1966), Becker (1993), Mussida and Picchio (2014) confirm the existence of a positive correlation between education and income, and that the gap in the level of formal education widens the personal income gap. Therefore, in order to narrow the income gap, the key point is to increase investment in formal education [3-7]. It is quite conceivable that the education level and its different levels can affect the income gap by improving the quality and skills of workers (quality and skill effect), promoting occupation conversion of workers (occupation conversion effect), improving labor productivity (productivity effect), and boosting labor mobility and transfer (labor flow effect), and so on.

Round 2

Reviewer 2 Report

I am not sure if the authors have understood my comments. I strongly suggested to improve the scope and implication of this working by referring latest published papers such as :

# Alam, G.M., Forhad, M.A.R. What makes a difference for further advancement of engineers: socioeconomic background or education programs?. High Educ (2021). https://doi.org/10.1007/s10734-021-00741-4

# Alam, G.M (2021) Do Urbanized Socioeconomic Background or Education Programs Support Engineers for Further Advancement? International Journal of Educational Reforms: https://doi.org/10.1177/1056787921998338

 

The authors nether look at them nor any current publications in this area. They need to refer the recent work in this area   

Author Response

In response to the reviewer’s comment, we revised the introduction and literature review in lines 44-83, 84-93 as follows: Since the reform and opening up, Central China has significantly improved urban educational level (the urban education refers to schooling and training that take place in large, densely populated areas with diverse populations), with average educational attainment reaching 10.25 years in 2020 (the study covers 6 provinces in Central China, including Shanxi, Anhui, Jiangxi, Henan, Hubei, and Hunan). At the same time, the income of urban residents in Central China grew rapidly. In 2020, the per capita disposable income of urban residents reached $ 5701, an increase of 8.24% from 2019 (data source: China Statistical Yearbook). However, the income gap of urban residents in Central China is still large. In 2020, the income disparity ratio of the total income of high-income group plus the middle and upper-income group to that of lower-middle income group plus the low-income group is about 2.71 (data source: China Statistical Yearbook). So what impact does urban education have on the income gap of urban residents in Central China? Does urban education expand the income gap of urban residents or narrow the income gap of urban residents in Central China? Urban education comprises three different levels: urban primary education, urban secondary education and urban higher education. The core purpose of urban primary education is to instil citizenship and socialisation skills for urban residents, while urban secondary education is about delivering adequate skills and knowledge to equip young people of city with the means to face challenges and advance their social and learning development. Urban secondary education also produces a semi-skilled labour force and supplies graduates who could go on to urban higher education. Urban higher education mainly provides a skilled workforce in various highly diverse fields of endeavour in city with professional qualifications, urban higher education mainly comprises university and polytechnic delivery modes, and it functions to produce a highly skilled labour force for specific vocations in city (Young and Hordern, 2020; Alam and Forhad, 2021) [1,2]. Does each specific level of urban education expand the income gap of urban residents or narrow the income gap of urban residents in Central China? To narrow the income gap while improving the income level of urban residents in Central China, which level of urban education should be developed? To address these questions, this paper empirically analyzes the impact of urban education level and its different levels on the income gap of urban residents in Central China, and provides suggestions for the formulation of scientific and reasonable urban education development policies to narrow the income gap of urban residents in Central China. This study helps to enrich the theory of educational economics and improve the research content of income distribution theory. It provides a new empirical basis for improving the income level of urban residents and narrowing the income gap of urban residents in Central China. As the income gap of urban residents has also widened in some other developing countries (Naito and Nishida, 2017; Marcella, 2021) [3-4], this study also provides a reference for other developing countries similar to the Central China to develop which level of urban education to narrow the income gap of urban residents.

Theoretically, education supports improving graduates' socioeconomic outcomes and careers by injecting citizenship values and making sure they are employable, but some studies showed that students with a lower socioeconomic status and prior engineering backgrounds in the same discipline do not succeed in subsequent programs and professional careers, compared to their higher socioeconomic status counterparts who have no previous engineering background, engineering education and career advancement are not saliently linked  (Alam and Forhad, 2021; Alam, 2021) [10,11]. Marginson (2019) argued that the relationship between education and work is heterogeneous, and it is impossible to formulate a theory to explain such complex dynamics [12].

Round 3

Reviewer 2 Report

The version can be accepted