Research Article |
Corresponding author: Shah Mir Mowahed ( shahmirmowahed785@gmail.com ) Academic editor: Marina Sheresheva
© 2025 Yang Jingjing, Shah Mir Mowahed, Mohammad Wais Sharif Zada.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Jingjing Y, Mowahed SM, Sharif Zada MW (2025) Impact of Imports and Exports on Inflation Rate in Afghanistan: Does Political Instability Matter? BRICS Journal of Economics 6(1): 119-140. https://doi.org/10.3897/brics-econ.6.e138160
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Stabilizing the Consumer Price Index (CPI) to protect the populace from the adverse effects of inflation necessitates appropriate measures at both political and economic governance levels. This study examines the impacts of imports (IM) and exports (EX) on inflation (CPI) in Afghanistan using data from 1990 to 2023. The findings from the Autoregressive Distributed Lag (ARDL) model indicate that both IM and EX significantly impact CPI in the short and long term. A robustness check employing the Kernel-based Regularized Least Squares (KRLS) machine learning technique further validates these results. The analysis confirms that international trade has a substantial and positive effect on CPI. Additionally, in the context of Afghanistan, political instability acts as a positive moderator, amplifying the influence of imports and exports on inflation. The study concludes that the country requires a reevaluation of its policies regarding exchange rates and economic growth to mitigate the negative effects of imports, exports, and political volatility on the stability of the CPI.
Afghanistan Economy, Imports, Exports, Inflation, Political Instability
Afghanistan’s economy, marked by its unique geopolitical landscape and internal challenges, has long been vulnerable to fluctuations in trade and inflation. In a country heavily reliant on imports, the dynamics of trade flows can have profound effects on the cost of living and stability of the economy. However, the influence of trade on inflation is not merely a matter of economic theory or practice: in Afghanistan, it is intricately tied to political issues. Large trade imbalances and a persistently massive gap between imports and exports define the nation’s economic environment, posing risks that could intensify inflationary pressures. Afghanistan’s trade deficit as of 2023 was at 6.798 USD billion, with USD 8.576 billion in imports and USD 1.777 billion in exports (
The dynamics of inflation in Afghanistan are closely linked to the cost of imported commodities that accounts for a significant portion of the consumer price index (CPI). In this relationship, the exchange rate pass-through effect is crucial; as the Afghani currency depreciates in value relative to other major currencies such as the US dollar, the cost of imported goods rises sharply driving up the rate of inflation. According to a Da Afghanistan Bank study, there is a 73.79% correlation between inflation and the exchange rate, meaning that changes in currency values have a serious effect on domestic prices (
Although imports are frequently criticized for contributing to inflation, exports also have an impact that should not be disregarded. Afghanistan’s export market is modest and primarily consists of low-value goods like agricultural and textile products. These sectors’ performance has the potential to influence domestic supply, which in turn may have an impact on inflation. For example, a significant rise in demand for exports may lead to a reduction in the supply of domestically produced goods driving up their prices. External factors, such as global commodity pricing and supply chain disruptions, may further complicate this relationship. Afghanistan’s heavy reliance on imports for essentials like food and fuel makes it especially vulnerable to shifts in international markets (
One should not ignore the broader economic context. Afghanistan’s economy has suffered greatly since the Taliban took power in August 2021, as evidenced by a precipitous drop in GDP and a major cutback in humanitarian assistance (
Effective policymaking in Afghanistan requires an understanding of how trade dynamics affect inflation as the country navigates its way to economic recovery in the face of persistent geopolitical uncertainty. By using econometric modelling and empirical analysis, this paper seeks to conduct a thorough examination of these linkages and provide important insights that can guide policymakers’ attempts to stabilize prices and foster sustainable economic growth by clarifying how changes in imports and exports affect inflation rates in Afghanistan’s economic environment.
The paper aims to examine how imports and exports affect Afghanistan’s inflation rates while taking political instability into account as a moderator. Research on inflationary tendencies in developing nations is abundant, but little is known about the precise dynamics of trade-induced inflation in Afghanistan, which creates a significant gap in the literature. Besides, even though Afghanistan’s 2016 entry into the World Trade Organization (WTO) was a significant step toward the country’s economic integration with the rest of the world, no previous study had fully investigated how this membership might affect economic stability or inflationary pressures. The absence of such studies leaves a crucial void in understanding how global trade frameworks can potentially mitigate inflation in post-conflict nations. Furthermore, the political instability brought about by the U. S. withdrawal and the Taliban’s subsequent takeover of the Afghan government in 2021 has further complicated the relationship between trade, inflation, and political stability by adding a new degree of uncertainty to the nation’s economic environment. By investigating the complex relationship between trade flows and inflation, the role of WTO membership in maintaining price stability and the potential moderating influence of political instability, this study seeks to close the gaps in research and provide new and thorough understanding of Afghanistan’s economic difficulties.
This paper analyzes the interplay between trade, inflation, and political instability in Afghanistan’s precarious post-conflict economy. It emphasizes the significance of political context for the study into the consequences of trade by examining the intricate ways in which imports, exports, and political volatility all work together to drive inflation. Ultimately, the paper challenges the conventional boundaries of economic analysis by showing that the true drivers of inflation in politically unstable regions are not only the forces of supply and demand but the broader socio-political fabric that influences the interaction of trade and inflation. In doing so, it contributes to the exploration of such fields as international trade, political economy, and development studies, establishing a foundation for future research that connects economic behavior with the unique political realities of developing nations.
Many researchers have examined the connection between inflation and trade flows, especially in developing and emerging nations. Since international trade is the main channel through which external economic forces affect domestic price levels, the importance of this relationship should not be underestimated. Prior research on this subject has mostly concentrated on how imports and exports affect inflation in larger economic contexts, paying special attention to trade liberalization, price stability, and the function of currency rates. The idea that trade plays a crucial role in reducing inflationary pressures through its impact on competition, market efficiency and access to foreign goods is usually supported by empirical data. Trade flows can help reduce inflation by improving resource allocation, increasing the supply of goods, and stabilizing domestic prices through integration with international markets.
In a related study,
The relationship between inflation and import prices in the USA is examined by
Using a Granger causality method,
The existing research suggests that imports, exports, and inflation rates interact in a complicated way. Imports frequently cause inflation through higher prices and supply chain weaknesses; increases in exports are typically associated with rising inflation because of improved domestic demand and price adjustments. These connections, however, have not been fully examined in relation to Afghanistan, especially considering the nation’s persistent political unrest and the economic fallout from the U. S. withdrawal. Since Afghanistan’s economic resilience has been severely undermined by the sudden end of international aid, it is crucial to comprehend how trade dynamics affect inflation in this particular setting. This paper offers a thorough examination of the connections between imports, exports, and inflation in the context of Afghanistan. It does this in an effort to educate policymakers on practical methods for maintaining price stability and encouraging long-term economic growth in a country that has to deal with excessive reliance on trade.
This study is based on time series data for Afghanistan from 1990 to 2023. It uses a number of important variables, such as the Consumer Price Index (CPI), Imports (IM), Exports (EX), GDP Per Capita (GDP), Exchange Rate (EXR), Political Instability (PI), Afghanistan’s World Trade Organization (WTO) membership, and the United States’ withdrawal from Afghanistan (USAW). The CPI is calculated using 2010 as the base year (2010=100), whereas IM and EX are expressed in the US dollars. The official USD exchange rate is reflected in EXR, while GDP is expressed as per capita real GDP in USD adjusted to 2015 constant prices, and TAX refers to taxes on international trade. Political stability and lack of violence are evaluated by PI, and estimates are given. The dummy variables for WTO accession and USAW are set to 0 before 2016 and 1 after that, and 0 before 2021 and 1 after that, respectively. The Trade Map and the World Bank database provided the data for every variable (see Table
Variables | Variables Definition | Data Sources |
CPI | Consumer Price Index (2010=100) | WDI |
IM | Goods and Services Import Value in US$ | Trade Map |
EX | Goods and Services Export Value in US$ | Trade Map |
PI | Political Stability and absence of violence (Estimate) | WDI |
EXR | Official Exchange Rate Afghani per US$ | WDI |
GDP | Per Capita Real GDP | WDI |
TAX | Taxes on International Trade (% of revenue) | WDI |
WTO | Afghanistan Accession to WTO (1 after 2016, 0 before) | Dummy |
USAW | USA Withdrawal from Afghanistan (1 after 2021, 0 before) | Dummy |
Furthermore, Table
Descriptive Statistics | CPI | IM | EX | PI | EXR | GDP | TAX |
Mean | 1.959 | 6.679 | 6.167 | -2.433 | 1.722 | 2.625 | 0.981 |
Maximum | 2.218 | 6.993 | 6.468 | -1.872 | 1.945 | 2.765 | 1.343 |
Minimum | 1.747 | 6.403 | 5.770 | -2.795 | 1.563 | 2.456 | 0.500 |
Std. Dev. | 0.167 | 0.211 | 0.177 | 0.210 | 0.106 | 0.094 | 0.264 |
Skewness | 0.244 | 0.316 | -0.380 | 0.531 | 0.681 | 0.322 | -0.265 |
Kurtosis | 1.427 | 1.418 | 2.497 | 3.185 | 2.490 | 1.667 | 1.737 |
Jarque-Bera | 3.844 | 4.114 | 1.176 | 1.647 | 2.994 | 3.106 | 2.658 |
Probability | 0.146 | 0.128 | 0.555 | 0.439 | 0.224 | 0.212 | 0.265 |
Observations | 34 | 34 | 34 | 34 | 34 | 34 | 34 |
The present study employs an empirical approach to examine the influence of IM and EX on CPI (Inflation) while accounting for the moderating role of PI in achieving the CPI variations in Afghanistan. The following equation (1) represents the econometric model of the linear association between these fundamental variables:
Ln(CPI)t = β0 + β1Ln(IM)t + β2Ln(EX)t + β3(PI)t + ui (1)
Before empirical estimation, all the variables were transformed using natural logarithm to standardize the dataset, generate stationary series and facilitate accurate estimations by removing heteroskedastic and outlier effects. Moreover, the model has been validated, and the omitted variable bias has been resolved by including five additional variables, namely EXR, GDP, TAX, WTO and USAW. Henceforward, the log-transformed econometric function of equation (1) can be rewritten as follows:
Ln(CPI)t = β0 + β1Ln(IM)t + β2Ln(EX)t + β3(PI)t + β4Ln(EXR)t +
+ β5Ln(GDP)t + β6Ln(TAX)t + β7(WTO)t + β8(USAW)t + ui (2)
In equation (1-2), Ln(CPI) is used as a proxy for inflation rate, ln(IM) represents the natural logarithm of import, Ln(EX) shows the natural logarithm of export, PI is the political stability index, Ln(EXR) stands for exchange rate, Ln(GDP) refers to GDP per capita level, Ln(TAX) is Tax on international trade, (WTO) is a dummy variable for Afghanistan membership in World Trade Organization in 2016, and (USAW) represents USA withdrawal from Afghanistan in 2021. Finally, ui represents the error term that accommodates any residual variability in the model that cannot be accounted for by the other variables.
The present research uses the ARDL bond test technique to estimate Model (2) and study the long- and short-term connections between perceived variables and CPI. The specific characteristics of time series data are critical to the choice of the most suitable methods of analysis. Time series data have an autoregressive attribute, which allows current values to be associated with historical ones. The sequential integration of variables and their cointegrating interactions play a major role in determining the best estimation framework for time series analysis. Fig.
Most economic factors exhibit temporal variation, i.e. they are non-stationary variables. Conventional estimation techniques, like ordinary least squares (OLS), yield unreliable and biased estimations when applied to non-stationary series. Therefore, improper application of estimation techniques in time series analysis without due regard for the stationarity characteristics of the series under investigation can result in spurious regression. The conventional approach to statistical estimation in applied econometrics is based on the presumption of normality, where the mean and variance become stable over time and it may happen that objectively non-connected variables are found to have significant connections according to regression results. Making inferences from such findings can result in serious errors.
In this study, the Augmented Dickey-Fuller (ADF) unit root test, created by
To find out whether there was cointegration between the variables after confirming their stationarity, we chose the ARDL bound cointegration test created by
The study used autoregressive distributed lag error correction framework created by
By allowing the lag of the dependent factor to be combined with the lags of the other independent variables, it also helps to overcome the problem of collinearity. Compared to alternative techniques within the parametric single-equation cointegration estimators’ category, the ARDL model can alleviate the second-order asymptotic consequences of cointegration. The ARDL model is based on several essential assumptions that include the absence of autocorrelation in the error terms, consistency of variance and mean throughout the model, normal distribution of the data, and variable stationarity (
Below is a mathematical representation of the ARDL model that incorporates the lagged error correction term (ECT), which indicates the pace of convergence of the long-run equilibrium state, as well as the derivation of empirical estimates for both short- and long-term effects:
∆Ln(CPI)t = β0 + β1Ln(IM)t – 1 + β2Ln(EX)t – 1 + β3(PI)t – 1 + β4Ln(EXR)t – 1 +
+ β5Ln(GDP)t – 1 + β6Ln(TAX)t – 1 + βakLn(CPI)t – k + βbkLn(IM)t – k +
+ βckLn(EX)t – k + βdk(PI)t – k + βekLn(EXR)t – k + βfkLn(GDP)t – k +
βgkLn(TAX)t – k + ECTt – 1 + μt (3)
Equation (3) shows the long and short-run coefficients which are specified by βa, …, βg and β1, …, β6 respectively. Similarly, Δ stands for first-difference operator and μt denotes the error term.
Additionally, the Akaike information criteria are used to calculate the lag length prior to performing an empirical computation using ARDL. Lastly, it should be mentioned that the identification of a long- or short-term cointegrating relationship does not ensure that the models used in research will remain stable in the course of the study. The Durbin-Watson statistic, the Breusch-Pagan-Godfrey heteroscedasticity test, the Breusch-Godfrey serial correlation LM test, the Ramsey RESET test, and the Jarque-Bera test were therefore used as residual diagnostics tests.
To confirm the most reliable outputs, the Kernel-based Regularized Least Squares (KRLS) machine learning algorithm approach was applied; it was proposed by
The Gaussian kernel utilized by KRLS is shown below:
(4)
In equation (4), xi and xj are the two associated dataset points with the squared Euclidean distance term (), and the parameter (σ2) which controls the width of the kernel. In addition, the kernel reaches its maximum value when comparing two data points, xi , and xj , that are identical (i.e., xi = xj). As the distance between xi and xj increases, the value of the kernel decreases and approaches zero.
Descriptive data are presented in Table
Table
ADF Unit Root Test | |||||
Variables | At level C | At 1st diff C | At level C&T | At 1st diff C&T | Outcome |
CPI | -0.016 | -7.060*** | -2.293 | -7.017*** | I(1) |
IM | -1.337 | -3.643** | -0.624 | -3.690** | I(1) |
EX | -2.989** | -5.872*** | -3.351* | -5.880*** | I(0) |
PI | -2.780* | -5.424*** | -2.600 | -5.343*** | I(0) |
EXR | 0.493 | -6.014*** | -1.480 | -6.182*** | I(1) |
GDP | -0.941 | -4.386*** | -0.298 | -4.478*** | I(1) |
TAX | -2.721* | -5.842*** | -3.667** | -5.979*** | I(0) |
Zivot Andrews Structural Break Unit-Root Test | |||||
Variables | Leve t-statistic | Break year | At 1st diff t-statistic | Break year | Outcome |
CPI | -4.420 | 2008 | -5.894*** | 2006 | I(1) |
IM | -3.781 | 2010 | -6.014*** | 2012 | I(1) |
EX | -5.387*** | 2013 | -6.821*** | 2018 | I(0) |
PI | -3.646 | 2007 | -5.812*** | 2003 | I(1) |
EXR | -2.791 | 2015 | -7.335*** | 2012 | I(1) |
GDP | -1.746 | 2007 | -6.235*** | 2002 | I(1) |
TAX | -2.795 | 2016 | -6.690*** | 2014 | I(1) |
Table
Variables | F-Statistics | T-Statistics | |||||||
CPI = F (IM, EX, PI, EXR, GDP, TAX) | 7.636** | -4.291* | |||||||
Kripfganz and Schneider’s critical and approximate p-values | |||||||||
Statistic | 10% | 5% | 1% | p-value | |||||
I(0) | I(1) | I(0) | I(1) | I(0) | I(1) | I(0) | I(1) | ||
F | 2.641 | 4.321 | 2.945 | 3.831 | 3.712 | 4.621 | 0.000 | 0.002 | |
T | -2.542 | -4.763 | -2.783 | -4.375 | -3.914 | -4.904 | 0.005 | 0.004 | |
ARDL Lag-Order Selection Criteria | |||||||||
Lag | LL | LR | FPE | AIC | HQ | SC | |||
0 | 68.843 | NA | 2.5e-06 | -4.389 | -4.344 | -4.249 | |||
1 | 149.839 | 161.990 | 2.1e-08* | -9.189* | -9.009* | -8.628* | |||
2 | 152.783 | 5.889 | 3.2e-08 | -8.785 | -8.471 | -7.804 | |||
3 | 161.993 | 18.420* | 3.3e-08 | -8799 | -8.351 | -7.398 |
We performed a sequential analysis prior to applying the ARDL technique to examine the short- and long-term effects of explanatory factors. In order to better understand the relationship between IM, EX, PI and CPI, benchmark regression and moderation effect exploration were required.
The findings of the benchmark regression analysis are shown in Table
Variables | Model-1 | Model-2 | Model-3 |
IM | 0.257*** (0.091) |
||
EX | 0.045** (0.019) |
||
PI | 0.360*** (0.038) |
||
EXR | 0.818*** (0.112) |
0.845*** (0.065) |
0.741** (0.064) |
GDP | 0.352* (0.180) |
0.339*** (0.113) |
0.353*** (0.105) |
TAX | 0.191*** (0.048) |
0.188*** (0.052) |
0.184*** (0.134) |
Constant | -0.539 (0.541) |
-0.566 (0.594) |
-0.623** (0.303) |
N | 34 | 34 | 34 |
Adj-R2 | 0.971 | 0.965 | 0.969 |
The moderating effect of Political Instability (PI) on the influence of IM and EX on CPI is displayed in Table
Variables | Model-1 | Model-2 |
IM | 0.257*** (0.091) |
0.257*** (0.091) |
EX | 0.105* (0.063) |
0.105* (0.063) |
PI | 0.182** (0.075) |
0.182** (0.075) |
IM*PI | 0.315** (0.087) |
|
EX*PI | 0.189* (0.048) |
|
Control | Yes | Yes |
Constant | Yes | Yes |
N | 34 | 34 |
Adj-R2 | 0.970 | 0.975 |
Reliance on imported goods that often increases during brief periods of stability becomes even greater because of limited domestic output and prices rising in the absence of competition. High prices are also a result of ongoing inflationary pressures, speculative pricing, and currency volatility. Besides, CPI can be impacted by improved supply chain capabilities and growing customer preferences for imports, especially when a small number of companies control a large portion of the market.
Similarly, the positive impact of EX*PI on CPI might also be a result of higher demand for Afghan products in politically stable environments, which could raise prices because of higher production costs or more competition in the market. In the case of Afghanistan, these dynamics highlight the intricate connection between political circumstances and economic conduct.
Table
Variables | Model-1 | Model-2 |
WTO | -0.076*** (0.027) |
|
USAW | 0.094*** (0.024) |
|
Control | Yes | Yes |
Constant | Yes | Yes |
N | 34 | 34 |
Adj-R2 | 0.972 | 0.976 |
The ARDL approach can be used to estimate the regression and draw conclusions about long-term impacts once the Boundary test has shown the presence of a long-term cointegration relationship among parameters. At this point, we analyze the long-term effects and investigate how IM, EX, and PI affect CPI over an extended period of time. Table
Variables | Long-run Estimation | Short-run Estimation | ||||
Coefficients | P-Values | Coefficients | P-Values | |||
IM | 0.214** | 0.028 | 0.198*** | 0.000 | ||
EX | 0.187* | 0.069 | 0.129** | 0.021 | ||
PI | 0.286*** | 0.007 | 0.319*** | 0.000 | ||
EXR | 0.769*** | 0.000 | 0.620** | 0.000 | ||
GDP | 0.305* | 0.057 | 0.217* | 0.057 | ||
TAX | 0.084** | 0.028 | 0.123* | 0.061 | ||
ECTt-1 | -0.701*** | 0.000 | ||||
Diagnostic Tests | χ2(P – Value) | Results | ||||
Durbin-Watson | 3.154 | |||||
Adj-R2 | 0.957 | |||||
Breusch-Godfrey LM Test | 3.504 (0.148) |
No serial correlation evidence | ||||
Breusch-Pagan-Godfrey | 7.591 (0.569) |
No heteroscedasticity evidence | ||||
ARCH | 0.159 (0.608) |
No evidence of heteroscedasticity | ||||
RESET | 4.625 (0.150) |
Model Correctly Specified | ||||
Jarque-Bera Test | 2.621 (0.208) |
Estimates of residuals are normal |
The results of additional residual diagnostic tests are also shown in Table
The current study examines the causal link between chosen indicators using point-wise differentials and the KRLS machine learning algorithm. By examining the forecasters’ marginal effects at each stage, the previously indicated empirical method enables us to investigate the structural changes in Afghanistan’s economic management. The effects of IM, EX, PI, and EXR are shown to be positive and significant in Table
Variables | Average | SE | P-Value | P25 | P50 | P75 |
IM | 0.071 | 0.010 | 0.000 | 0.170 | 0.302 | 0.372 |
EX | 0.045 | 0.021 | 0.042 | 0.035 | 0.060 | 0.061 |
PI | 0.032 | 0.002 | 0.000 | 0.021 | 0.086 | 0.098 |
EXR | 0.098 | 0.043 | 0.018 | 0.894 | 0.696 | 0.622 |
GDP | 0.051 | 0.043 | 0.501 | 0.124 | 0.157 | 0.234 |
TAX | 0.013 | 0.009 | 0.105 | -0.198 | 0.208 | 0.162 |
Diagnostic | ||||||
Lambda | Tolerance | sigma | Eff.df | R2 | Looloss | |
0.0108 | 0.0428 | 0.0174 | 4.1633 | 0.9888 | 33.1309 |
According to the data displayed in Fig.
In this study we aim to find out how imports (IM), exports (EX), and political instability (PI) affect Afghanistan’s Consumer Price Index (CPI), taking into account the impact of important macroeconomic factors like GDP, taxation (TAX), and exchange rates (EXR). The study covers the years 1990–2023, offering a thorough examination of the ways in which both domestic and international factors influence changes in the country’s price level. According to the findings, the currency rate volatility, GDP growth, and taxation policies all have a major impact on Afghanistan’s CPI. The analysis has shown that rising imports and exports have compounding impacts on local market pricing and availability of products and services. Political instability exacerbates price volatility, interferes with market systems and undermines economic stability. Together, these factors show that a complex interaction between fiscal policies, external trade activity, and sociopolitical issues shapes Afghanistan’s CPI.
A number of policy initiatives are suggested to address the variables affecting Afghanistan’s Consumer Price Index (CPI). It is crucial to stabilize the exchange rate through export diversification, formal remittance inflows, and larger currency reserves. Reliance on imports can be decreased by encouraging home manufacturing and economic diversity, while fair trade laws should make sure that exports do not jeopardize domestic supplies. The impact of inflation on vulnerable households can be alleviated by decreasing the tax burden on necessities and implementing social programs involving cash transfers or subsidies.
Economic resilience depends on political stability, which calls for improved governance and inclusive discourse. Import expenses can be decreased and prices can be stabilized by investments in trade infrastructure to ensure expedited customs procedures and optimization of taxes on international trade. In order to combat instability, trade agreements and development assistance should be the main goals of regional alliances and international collaborations. Together, these actions can lessen inflationary pressures and lay the groundwork for long-term steady growth.
This study has a number of limitations that should be taken into account. First, there can be issues with the data’s dependability and accessibility. The quality and representativeness of the data sources, which may have biases or limits, are critical to the study’s conclusions. Second, even if the study finds connections between many characteristics, it might be difficult to prove causation in observational research. Causal links between the variables under analysis cannot be conclusively established by the study. Thirdly, it is important to note that the results can be context-specific and only applicable to the country being studied, therefore extending these findings to other geographic or economic situations cannot be recommended.
Yang Jingjing: Supervision, Writing – review & editing, Validation, Resources, Project administration, Funding acquisition. Shah Mir Mowahed: Writing – review & editing, Writing – original draft, Methodology, Investigation, Formal analysis, Conceptualization, Software. Mohammad Wais Sharif Zada: Software, Validation, Visualization, Writing – review & editing, Investigation, Data curation.
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
This work was supported by the research on impact of Hunan Talent policy to technology innovation. Funded by Hunan Provincial Social Science Foundation, Reference No.22YBA027.
Data is available up-on request.