## 4 Case Study
### Data Acquisition and Result
#### 4.2.3 Differences in the Development Level of City-Industry Integration  
As Panzhihua is the only city in the Panxi Economic Zone in this paper, the study of its regional differences was not studied. It can be seen from Figure 6 that during the sample investigation period, the Gini coefficient and Theil index had strong consistency in the changing trend, and their increase and decrease were synchronous, indicating that both indicators can corroborate each other in measuring the imbalance of city-industry integration. The Gini coefficient of the city-industry integration degree between economic zones fluctuated between 0.16 and 0.2, and the Theil index fluctuated between 0 and 0.02. From the Gini coefficient, the development difference between economic zones was within a reasonable range, and the fluctuation range was small. This shows that while regional differences have expanded after slight fluctuations in the past decade, Sichuan remains focused on overall balanced development.  
Decomposing the Theil Index can effectively derive the sources of regional development differences, as shown in Table 7. Overall, the development level of city-industry integration in Sichuan Province had a slight difference, and the spatial imbalance was mainly due to intra-regional differences. From 2010 to 2019, the Theil index increased from 0.0047 to 0.0052, and the difference gradually expanded. The intra-regional difference index increased from 0.0042 to 0.0044, always much higher than the inter-regional difference index. Therefore, the main reason for the spatial imbalance of city-industry integration in Sichuan was the internal differences of various economic zones. From the difference of city-industry integration degree within the economic zone, the Chengdu Plain Economic Zone had the largest value, while the other two economic zones had the smallest and most stable values. Moreover, the contribution rate of the Theil index of the Chengdu Plain Economic Zone was the highest, which decreased from 87.80% to 82.55%. It indicates that the unbalanced development of city-industry integration in the Chengdu Plain Economic Zone has been alleviated to a certain extent, but the internal differentiation is still serious. This is mainly because the development level of Chengdu, Deyang, and Mianyang is much higher than that of the other five cities. South Sichuan and northeast Sichuan economic zones had the lowest contribution rate, and the development level of city-industry integration was balanced.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Region**} & \multicolumn{2}{c}{**Chengdu Plain**} & \multicolumn{2}{c}{**South Sichuan**} & \multicolumn{2}{c}{**Northeast Sichuan**} & \multirow{2}{*}{**Panzhihua**} \\  & \multicolumn{2}{c}{**Economic Zone**} & \multicolumn{2}{c}{**Economic Zone**} & \multicolumn{2}{c}{**Economic Zone**} & \\ \hline \multirow{3}{*}{Social services} & 2010 & 3.0621 & 1.3298 & 1.6086 & 0.3882 \\  & 2019 & 2.9938 & 1.3373 & 1.6316 & 0.6313 \\  & Change & \(-\)0.0683 & 0.0075 & 0.0230 & 0.2431 \\ \hline \multirow{3}{*}{Urban construction} & 2010 & 3.1851 & 1.3388 & 1.7931 & 0.3819 \\  & 2019 & 3.2248 & 1.3354 & 1.8320 & 0.3837 \\  & Change & 0.0397 & \(-\)0.0034 & 0.0389 & 0.0018 \\ \hline \multirow{3}{*}{Ecology and environment} & 2010 & 3.1164 & 1.6486 & 2.0382 & 0.3973 \\  & 2019 & 2.9344 & 1.8503 & 1.9834 & 0.3614 \\  & Change & \(-\)0.1820 & 0.2017 & \(-\)0.0548 & \(-\)0.0359 \\ \hline \multirow{3}{*}{Science and technology} & 2010 & 2.6773 & 1.0293 & 1.0989 & 0.2893 \\  & 2019 & 2.7376 & 1.0297 & 1.0845 & 0.2644 \\ \cline{1-1}  & Change & 0.0603 & 0.0004 & \(-\)0.0144 & \(-\)0.0249 \\ \hline \hline \end{tabular}
\end{table}
Table 6: _Cont._