رابطه مبادله ، نرخ واقعي داخلي ارز وارداتي و صادراتي و نرخ واقعي داخلي ارز در ايران

Terms of Trade, Internal Real Exchange Rate for Imports and Exports and the Internal RER in Iran

While the external RER3 measures the relative domestic and foreign price expressed in a common currency by contrast, the internal RER measures a relative price between two different categories of domestic goods: tradable and nontradables. Internal RERs may be based on two- three- or multi macroeconomic models. The first internal RER concept was developed based on models that incorporated two types of goods, tradables and nontradables. These two good models necessarily assume that the terms of trade between exportables and importables are fixed so that these can be aggregated into a single composite tradable good. Consequently, these models are not very useful for analyzing the effects of changes in the external terms of trade, which are often important determinants of exchange rate movements in developing countries. In choosing a good measure for internal RER, there must be a distinction between two goods and three goods models and between border and domestic prices and also between direct methods and proxies. There are three factors which influence our choosing: Differential productivity in traded and nontraded goods,changes in trade taxes, administrated prices and other commercial policies that drive a wedge between internal and external prices, fluctuations in terms of trade, which can shift relative prices much more sharply in developing countries. The internal RER in the two - good framework can be calculated directly as a weighted average of the RER for exports and the RER for imports. But in the situation of terms of trade fluctuations, the RER for Exports and the RER for imports may move into different direction then the aggregation of these two into a single composite tradable good may hide such movement and Compatibility of the domestic prices. With this matter in view itʹs better three goods framework be chosen. We know the different factors have diverse effects on internal and external RER, and then the question is that which of them can be measured more correctly and which of them are more appropriate for Iran? Indeed in this paper these aims are followed: To review and operationalize the various definitions of the internal RER as a starting point for the empirical measurement of these concepts for Iran, to relate these theoretical definitions to actual price and national accounts data available in Iran, an apprise of terms of trade fluctuation in Iran with the use of three goods internal RER and its efficiency in Iran. In this paper, first conceptual and theoretical definitions of the three-good internal RER with an eye on terms of trade fluctuations are introduced and then different indexes of that for Iran are computed. Then the behavioral trend of these different indexes is discussed and their efficiency is tested, followed by conclusion and remarks.