عنوان مقاله [English]
The main purpose of this study is to evaluate Iran`s tax system efficiency through tax elasticity and buoyancy indexes. In doing so, using tax income and tax base data on various types of direct and indirect taxes during the period of 1980-2015, initially the buoyancy of taxes was estimated by the ARDL and ECM models, and then, tax elasticity was estimated considering the proxy of tax policy and by a non-linear model. Eventually, the sensitivity of buoyancy estimation to inflation and economic expansion and economic contraction was evaluated. Results suggest that in long term buoyancy and elasticity for various taxes are almost equal. But in short terms, elasticity is greater than buoyancy. According to this fact, tax policies do not play a significant role in tax income increment, and tax income increases due to tax basis growth. Also, inflation only affects buoyancy rate in short terms, and long term buoyancy is independent from the inflation changes. Furthermore, direct taxes are not flexible in terms of periods of economic expansion and economic contraction, and only taxes on goods and services have a compatible behavior into the periods of economic expansion and economic contraction.