Regional Tax Security Forecasting under Alternative Scenarios: Evidence from an ARIMA Model

This study develops and interprets ARIMA-based forecast scenarios for strengthening tax security in Uzbekistan and for supporting the design of regionally differentiated fiscal policies. Tax security is treated as an institutional and economic condition in which the tax system is capable of generating stable, predictable, and sufficient public revenues while remaining resilient to internal and external risks, including tax-base erosion, the shadow economy, tax arrears, digital business models, and weaknesses in tax administration. The empirical analysis uses annual data for 2016–2025 on total state-budget tax revenues, direct taxes, and indirect taxes. A Box–Jenkins time-series framework is applied, combining stationarity assessment, model identification, information-criterion comparison, and residual diagnostics. The selected specifications are ARIMA(0,1,0) with drift for total tax revenues and direct taxes, and ARIMA(0,1,1) with drift for indirect taxes. Model adequacy is evaluated using the Akaike and Bayesian information criteria, the augmented Dickey–Fuller procedure, the Ljung–Box test, and the Jarque–Bera test. The results indicate no statistically evident residual autocorrelation or severe departure from normality in the selected models, although the limited number of annual observations requires cautious interpretation. Forecasts suggest that total tax revenues may increase from UZS 308,521.8 billion in 2025 to UZS 457,027.1 billion in 2030, representing cumulative nominal growth of approximately 48.1 percent. Direct taxes are projected to reach UZS 152,976.2 billion, while indirect taxes may reach UZS 153,910.3 billion by 2030. The study argues that higher revenue alone is not equivalent to stronger tax security. Sustainable improvement requires risk-based control, real-time monitoring, digital audit, artificial-intelligence-supported compliance analysis, systematic Tax Gap estimation, reduction of tax arrears, and more effective use of regional tax potential. The forecasts therefore provide a quantitative baseline for fiscal planning rather than a complete measure of tax security.