Valstybės finansų ekonometrinis modeliavimas

Abstract

The accurate (exact) prediction of tax revenue is a very important task for state budget planning. Both underestimation and overestimation of the planned revenue could cause problems in case the revenue is used to finance government functions. In the past few years planning of profit tax revenue was not very exact: the sum of the profit tax collected was considerably smaller or considerably larger than the planned profit tax revenue. The difference between the actual and planned revenue was about 12–56 % every year. There are several related factors which aggravate profit tax revenue modelling. It is doubtful if the indicator of profit tax revenue is stationary. The assumption of the stationarity of indicators is usually made when applying econometric models to the indicators. This problem is caused by a frequent change of the Profit tax law. In addition, transitional processes, invoked by privatization, integration to EU, and etc were typical of the Lithuanian economy in the past few years. Therefore very general equations used to describe the profit tax revenue of macroeconometric models of many countries are not relevant to model and predict the profit tax revenue in Lithuania. In order to predict budget revenues accurately, their modelling methodology needs to be created so as to be effective in the situation where regression relations are complicated while disposable series of observations are rather short (the quarterly profit indicators have been known since 1998 in Lithuania). The objective of this dissertation is to develop the compound methodology of profit tax modelling and predicting, based on the use of legal information, economic information, and analysis of statistical relations. The main attention is paid to the analysis of profit tax revenue and the two-stage modelling methodology is presented here. Financed by the Lithuanian State Fund of Science and Studies, the project of “Mathematical Models of Lithuanian Economy to Predict Processes of Macroeconomy”, aimed at the creation of a macroeconometric model of Lithuanian economy, have been pursued for several years. The system of equations of the government finances sector is an important part of the project and the last part of the dissertation is dedicated to its formation.