The Gap between Urban and Rural Development Levels Narrowed

The difference between urban and rural development levels (URDL) and the deficiency of rural development level have become the weak points for China to achieve balanced and high-quality development. In order to reveal the changing trend of urban-rural differences in China over the years and provide a reference for the policy-making of the balanced development of urban and rural areas and high-quality economic development, this paper uses the United Nations Development Program-adjusted Human Development Index (HDI) calculation method to calculate the urban and rural areas, based on 1995–2017 national time series data and provincial panel data. On this basis, this paper uses the Logarithmic Mean Weight Divisia to decompose the dynamic changes of the difference of URDL and analyzes the spatial equilibrium of the change trend of the differences of URDL, supplementing the shortcomings of the existing literature which only focuses on income, education, and other local areas and lacks continuity and comparison. The research finds that 1. based on the time series analysis of the difference of URDL, this paper firstly proposes the “inverted U” curve for the difference of URDL in China, which shows that the difference of URDL in China has experienced a process from expansion (1995–2001) to high fluctuation (2001–2011) to continuous convergence (2011–2017). 2. From the factor decomposition effect of the difference of URDL, the difference expansion period is caused by the increase in the gap between the Health Index, the Education Index, and the Income Index. With the decline in the gap between education levels and life expectancy, the growth trend of China’s urban-rural gap has been suppressed, and it has entered a high platform period with relative small fluctuation. After 2011, benefiting from the large decline in income level gaps, China’s urban-rural difference has entered a period of convergence. 3. From the perspective of the spatial evolution characteristics of the gap of URDL, the overall coefficient of variation of the country has shown a downward trend. The degree of spatial equilibrium is gradually increasing, and the overall changes in the east, west, and northeast are the same as the overall trend of the country. The decline in the northeast is the largest, the west is the second, and the east is the least. The middle shows a slight upward trend, but the value of each year is always smaller compared with other regions. Generally speaking, the gap of URDL is relatively good in the middle and northeast, followed by the east, and there is still much room for improvement in the balance of the west.


Introduction and Literature Review
As a developing country, China's urban and rural development has typical dual-structural characteristics. e countryside has made great contributions in the process of China's economic development, but the differences between urban and rural development levels and insufficient rural development levels have become the shortcomings of China's balanced and high-quality development. From the report of the 16th National Congress of 2002 on "coordinating urban and rural economic and social development" to the report of the 17th National Congress of 2007 on "urban and rural integration" to the 2013 ird Plenary Session of the 18th Central Committee of the People's Republic of China on the issue of "new urban-rural relations" and the report of the 19th National Congress of 2017 on "urban-rural integration development", the emphasis on the imbalance between urban and rural development has been increasing. Revealing the gap between urban and rural development and analyzing the causes of development differences not only allow us to clearly understand the changing trends of urban and rural development differences but also provide a reference for balanced urban and rural development and policy-making of economic high-quality development.
Urban-rural difference is an important area for studying the economic and social development of developing countries. Generally speaking, the research on urban-rural differences includes two areas, one is to comprehensively and holistically analyze the urban-rural differences, and the other is to conduct research on urban-rural differences in a certain area such as education and income.
In terms of comprehensive and holistic analysis, the published literature mainly conducts research from qualitative and quantitative methods. e qualitative research method mainly uses qualitative analysis with multielement description and combines with the empirical judgment of researchers. For example, Wang and He studied the gap between urban and rural development from 1978 to 2003 [1], Guo studied the gap between urban and rural areas before 2003 [2], and Zhong et al. and others studied the urban-rural gap before 2007 [3]. It is relatively consistent that almost all of the qualitative research papers [1][2][3][4][5][6][7][8][9][10][11] that study the gap between urban and rural areas believe that with the economic development, the gap between urban and rural areas in China is expanding.
To sum up, although China has accumulated some research results on the issue of urban-rural gap, the overall trend of urban-rural development differences is not clear. Concerning the research on the differences between urban and rural areas in specific fields such as income and education, the conclusions are highly fragmented due to the differences in the fields. It can only be concluded that the trend of changes in the specific field but cannot be used to infer the overall trend of urban and rural differences; while for comprehensive and holistic research, the number of papers is very limited, and the continuity of the research is relatively lacking. For example, Song and Ma [12] used the Human Development Index to conduct research. However, there has been no relevant literature for follow-up and comparative studies since 2002, which cannot reveal the longer-term period, especially the current trend. In comprehensive and holistic research, studies that judge the differences between urban and rural development through qualitative descriptions are difficult to obtain consensus due to the differences in researchers' knowledge background and research experience, and the continuity and comparability of the research are also relatively weak. In order to better understand the changing trend of China's urban-rural relations, and analyze and determine the future and long-term changes, this paper will use the United Nations Development Program (UNDP)-adjusted Human Development Index calculation method widely recognized by the international community to analyze and calculate the national time serial data from 1995 to 2017 and the panel data of each province, and reveal the overall trend of China's urban-rural development differences, analyze the driving factors of urban-rural development differences, and provide basic reference information for a comprehensive understanding and analysis of China's urban-rural development and change trends.

2.1.
e Difference between the Urban and Rural HDI. Based on the UNDP's adjustment of the subindex and weighting method of the Human Development Index in 2010, the available data in this paper are used to calculate the difference between the urban and rural Human Development Index in China according to the latest index system measurement method (formula (1)). e calculation method (due to the lack of statistics on the expected education of urban and rural areas, the Education Index in the Human Development Index only includes the average years of education) is as follows: In formula (1), HDI i is the Human Development Index in year i, LEI i is the Health Index in year i, EI i is the Education Index in year i, II i is the Income Index in year i, EL i is the life expectancy in year i, EL min is the minimum life expectancy, EL max is the maximum expected life expectancy, PGNI i is the per capita GNI (2011, PPP $) in year i, PGNI min is the minimum per capita income, PGNI max is the maximum per capita income, AEY i is the average years of education in year i, AEY min is the minimum value of average years of education, AEY max is the maximum value of average years of education, PPR i is the proportion of the primary school population in year i, JPR i is the proportion of junior high school population in year i, SPR i is the proportion of high school population in year i, and ACPR i is the proportion of population of university and above in year i. Among them, EL min , EL max , PGNI min , PGNI max , AEY min , and AEY max are shown in Table 1. e remaining data sources and processing methods in the HDI calculation formula are as follows. e calculation data sources and processing methods are as follows: (1) Sources and processing methods of per capita income data: the HDI methodology uses the US dollar GNI index measured in purchasing power parity (PPP) in 2011, and China's GDP statistics cannot be directly substituted into the calculation. is paper uses the ratio of per capita GDP data measured in RMB prices of the year based on the China Statistical Yearbook to GNI data measured in 2011 PPP prices to obtain a conversion factor. Based on this conversion factor, the national and local GNI data measured in 2011 PPP prices are calculated.
(2) Sources and processing methods of life expectancy data: the national urban and rural life expectancy data only contain the year 2000's statistical data, so this paper quotes urban and rural life expectancy data from 1995 to 2000, 2005, and 2009 in published papers [12,46]. Based on the above methods, the calculation formula for the difference between urban and rural development levels is

Logarithmic Mean Divisia Index. Logarithmic Mean
Divisia Index (here after referred to as LMDI) is a more commonly used research method to analyze different variables based on the magnitude and the change of influence. is paper uses LMDI to decompose the changes in the Human Development Index differences across the country and provinces and explores the main reasons affecting the changes in the Human Development Index from the aspects of Health Index effect, Income Index effect, and Education Index effect.
Logarithmic formula (1) gives Let the change in the difference between the urban and rural Human Development Index from the national T-j period to the T period be ΔM, then

Complexity
In formula (4), ΔLEI, ΔEI, and ΔII represent the changes in the urban-rural differences of the country's Health Index, Income Index, and Education Index during the period T-j∼T, respectively.

Coefficient of Variation.
China has a vast territory, there are differences in resource endowments and natural conditions in different provinces, and there are also significant differences in economic and social development, resulting in spatial equilibrium differences in urban and rural human development levels across the country and in various regions. e calculation methods that reflect the spatial equilibrium development mainly include Gini coefficient, eil Index, coefficient of variation, etc. is paper uses the coefficient of variation to measure the magnitude and trend of the gap between urban and rural human development across the country and regions according to the availability of data and research demand, and explain the spatial equilibrium of the gap between urban and rural development levels across the country and regions. e regional division is based on the commonly used 10 : 6: 11 : 3 classification standard in the national statistics (Table 2)(there are 30 provinces in total due to the difficulty of data acquisition in Tibet), which divides all provinces in China into four regions: east, middle, west, and northeast. e calculation method based on the gap between urban and rural human development to reflect the spatial equilibrium development is as follows: In formula (5), CV i represents the coefficient of variation of the gap between urban and rural human development levels in national, eastern, central, western, and northeastern countries in year i. M i represents the gap in human development in national urban and rural areas in year i, and M ij represents the gap in human development level between urban and rural areas in province j in year i. m represents the number of provinces included in each region.

e Trend of Human Development Level Difference between Urban and Rural
Areas. From 1995 to 2017, the differences of human development levels between urban and rural areas in China showed an "inverted U-shaped" structure, which can be roughly divided into three stages (Table 3 and  Analysis are based from the perspective of the factors that affect the future change trends in urban and rural human development levels. First, in terms of income level differences, the per capita disposable income ratio of urban and rural residents in China has shown a linear decline after reaching its peak in 2003 (the ratio of per capita disposable income of urban and rural residents calculated according to the China Statistical Yearbook). With China's balanced development and the implementation of poverty alleviation policies, the downward trend is expected to be consolidated. Secondly, in terms of the differences in health levels, the Health Index of Chinese cities and towns in 2017 has reached 0.910, which is slightly lower than that of the United States (0.916) and at a higher level. With the popularization of rural basic medical facilities and the increase of new rural cooperative medical insurance rate of farmers, the life expectancy in rural areas will also increase, and the difference in life expectancy between urban and rural areas is expected to narrow. ird, in terms of educational level differences, the advancement of policies and measurements such as urban-rural integration and urbanrural education balance provide guarantees for narrowing the gap between urban and rural education levels. Based on the trend analysis of the above three influencing factors, it is carefully determined that China's future urban and rural human development level differences will continue to narrow.
e inverted U-shaped curve of urban-rural gap also reflects the characteristics of China's economic and social development in the same period. In the late 1990s and the beginning of the 21st century, China has experienced rapid industrialization and urbanization, which means that labor, capital, and other production factors have gathered in central cities, and education and medical resources have also been inclined to urban areas. In this way, the difference between urban and rural development levels has been widening. In 2010, China became the second largest economy in the world. In the same year, China's industrialization entered the late stage (Huang, QunHui, Chaoxian Guo, Yanhong Liu, and Wenlong Hu, 2017, Sustainable Industrialization and Innovation Driven. Beijing: Social Science Academic Press. e level of industrialization is comprehensively calculated by five indicators, namely, per capita GDP, urbanization rate, industrial structure, employment proportion of primary industry, and proportion of added value of the manufacturing industry). Environmental pollution and resource constraints gradually emerged. In 2012, when the new government took office, China's economic development concept and model began to adjust. Changing the growth model and promoting the construction of ecological civilization gradually have been written into the development plans and implemented from the central to the local level, which means that the economic development has shifted from focusing on the speed of development to the quality of development; the industrial layout is more Complexity

Factors Affecting Decomposition of the Differences in
Urban and Rural Human Development. According to formula (4), changes in the gap between rural and urban development in China can be decomposed into changes based on three index effects: Health Index, Income Index, and Education Index. If the effect value is positive, it indicates that the index is promoting the expansion of the urban-rural gap; if the effect value is negative, it indicates that the index has contributed to reducing the urban-rural gap. From the comparison of the constituent index effects at different time periods, the expansion of urban-rural disparities in 1995-2001 was the result of the joint promotion of Education Index, Medical Index, and Income Index. e urbanrural gaps in these three fields are expanding and driving the overall urban-rural gap with the Health Index being the largest driving effect which has a decomposition effect value of 0.0047, followed by the Income Index of 0.0030, and the minimum Education Index of 0.0028. During the high fluctuation period of the urban-rural gap from 2001 to 2011, the rapid growth of the urban-rural gap was controlled, mainly due to the decline in the urban-rural education gap and life expectancy gap. Although the income gap was increasing, this increase was less than the decline in the health gap and Education Index gap; during the convergence period between 2011 and 2017, the gap between urban and rural areas showed a relatively stable decline, mainly due to the sharp decline in the urban-rural income gap. e education gap expanded during the period, but the expansion was smaller than the reduction in the urban-rural income gap and health gap. In the future, in order to maintain a steady trend of continuous decline of the gap between the urban and rural areas, the declining trend of income and Health Index differences between urban and rural areas needs to be continued, the widening education gap needs to be converted, and the Education Index needs to be made a positive factor in narrowing the gap of the Human Development Index between urban and rural areas (Table 4).

Analysis of the Spatial Equilibrium of the Difference between Urban and Rural Human Development.
According to formula (5), the smaller the coefficient of variation, the better the spatial equilibrium of the urban and rural Human Development Index gap ( Figure 2). Conversely, the larger the coefficient of variation, the lower the equilibrium of the urban and rural Human Development Index gap in the region. e calculation results show that the country's overall coefficient of variation is declining, from 0. 24   Note: The numbers in brackets in Table 4 are the contribution rates of the corresponding constituent indexes.
Complexity drop of 0.06. e coefficient of variation in the middle increased slightly from 1995 to 2017, from 0.09 to 0.12.
From the change characteristics of the four regional coefficients of variation, the value of the coefficient of variation in the west is significantly higher than that in the country and the three regions in the east, middle, and northeast. Although the coefficient of variation of the western region has decreased significantly compared to 1995, the coefficient of variation in the west is still significantly larger than that of the country and the other three regions. e northeast has become the region with the largest decrease in the coefficient of variation since 1995-2007, with a decrease of 0.13, which is higher than 0.1 in the west and 0.06 in the east. Which is also higher than the country's overall 0.06. Although the coefficient of variation of the middle region showed an upward trend from 1995 to 2017, because the value of the coefficient of variation has always been at a low level, the increase was generally small, and its equilibrium was relatively good in the four regions. erefore, from the variation characteristics of the four regional coefficients of variation, the equilibrium of the gap between the urban and rural Human Development Index is relatively good in the middle and northeastern provinces, followed by the east, and there is still much room for improvement in the balance of the west. (1) Based on the time series analysis of the urban-rural HDI, this paper firstly proposes an "inverted U" curve for the difference of human development level between urban and rural China, which shows that the gap of human development levels between urban and rural China has undergone a process from expansion to high fluctuations to continuous convergence; this "inverted U" curve can be divided into three periods as time develops: the expansion period (1995)(1996)(1997)(1998)(1999)(2000)(2001), the high-fluctuation period (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011), and the convergence period (2011-2017).

Conclusion and Policy Implications
(2) Judging from the decomposition effect of the gap between the urban and rural human development levels across the country, the gap expansion period is caused by the joint promotion of the Health Index, Education Index, and Income Index; the gap between urban and rural areas has been narrowed in the high-fluctuation period; the convergence period is reflected in the overall decline in the gap between urban and rural areas, mainly due to the decline in the Income Index and the Health Index. e Education Index has become a factor that widens the gap, but due to the large decline in the Income and Health Index, the period as a whole shows a trend of narrowing the gap. (3) From the perspective of the spatial evolution characteristics of the gap between urban and rural human development, the overall coefficient of variation of the country shows a downward trend, and the degree of spatial equilibrium is gradually increasing. e overall change trends in the east, west, and northeast of the country are the same, showing a downward trend. e decline is the greatest in the northeast, followed by the west, and the least in the east; the middle shows a slight upward trend, but its values in each year have been smaller compared to other regions. Generally speaking, the gap between urban and rural human development levels is relatively good in the middle and northeast, followed by the east, and there is still much room for improvement in the balance of the west.
Based on the above conclusions, this paper proposes the following suggestions on how to further narrow the gap between urban and rural areas: first, based on the "inverted U" curve of the gap between urban and rural human development levels proposed in this paper, it shows that China's urban-rural gap and coordinated urban-rural development have entered a new stage. Further research is needed to identify the main problems, difficulties, action ideas, and paths to reduce the gap between urban and rural areas in the new stage and new period, and provide a theoretical research basis for solving the imbalance between urban and rural development and promoting the development of urban-rural integration; second, the research in this paper shows that since 2011, the gap between the urban and rural Human Development Index in China has shown a general trend of convergence. e narrowing of the gap in income and health development is the main reason for the narrowing of the gap between urban and rural areas. e  8 Complexity imbalance in the development of urban and rural education needs attention. e evaluation of the adequacy, the intensity, and effectiveness of the implementation of the formulation of urban-rural balanced education policies is conducted, key issues are identified, and implementation solutions are explored. ird, from the perspective of the regional equilibrium of the gap between urban and rural human development, the balance of the west is still significantly lower than other regions. It is necessary to continue to vigorously promote and implement policies and measures to promote economic and social development in the western region.
rough efficient implementation of policies and the provision of accurate assistance to the western region, we can promote the improvement of the overall development level of the western region and reduce the gap between urban and rural development, achieve the overall balanced development of the western region, and also promote the overall balanced urban and rural development of the whole country.
Limited by the availability of data, the accuracy of some indicators in this study can be improved. Due to the lack of long time series of urban and rural life expectancy data statistic in China, the Health Index can only be calculated by the interpolation method, and showing a general trend of change, hopefully, annual statistics will be available in the future. As to further study next step, the team wish to check the data availability of other countries and carry out international comparison to explore the change law of the Human Development Index based on the studies of various kinds of countries including developed and developing countries, so that the study can better guide and serve the balanced economic and social development of developing countries.
e "Human Development Index related indicators for maximum and minimum criteria," "Education Index, Health Index, Income Index, and Human Development Index by urban and rural areas in China," "decomposition effects of the differences in urban and rural Human Development Index," and "variation coefficients of human development gaps between urban and rural areas in country and regions" data are included within the article. e "per capita disposable income of urban and rural residents in China" data are available from the "China Statistical Yearbook (2018)" (http://www.stats.gov.cn/tjsj/ndsj/2018/ indexch.htm).

Conflicts of Interest
ere are no conflicts of interest to declare.