Open Economy Macroeconomics: The IS-LM-BP Model
When we open the economy to international transactions we have to take into account the effects of trade in goods and services (i.e. items in the current account) as well as trade in assets (i.e. items in the capital account). Opening the economy to international trade in goods and services means that we have to take into account the increased demand for our goods by foreigners (our exports), as well as the decreased demand for our goods that occurs because we purchase foreign goods (i.e. our imports). Total expenditures in an open economy are C + I + G + NX, where NX -- net exports -- is equal to the level of exports (X) less the level of imports (V). Thus, our exports (X) represent…show more content… Thus, the relative price of that foreign good has risen and therefore, less of it will be purchased by domestic residents. So, an increase in e will cause a decrease in imports: a higher e raises the relative cost of foreign goods and therefore reduces V. Conversely, a decrease in e lowers the relative price of foreign goods and therefore increases V. Thus, imports are determined by domestic income levels and the exchange rate. An increase in Y or a decrease in e causes V to increase. A decrease in Y or an increase in e causes V to decrease.
The effect of opening the economy to trade in goods and services, is that the IS curve needs to be specified for a given exchange rate. The IS curve still depicts the combinations of i and Y for which the level of total expenditures equals the level of production, but now, in addition to being determined by the interest rate, total expenditures are also determined by the exchange rate (since the exchange rate affects the level of NX). Under a fixed exchange rate regime, the IS curve is fixed (unless there is a change in government spending or tax rates, or the government devalues or revalues the currency). Under a flexible exchange rate regime, the price of foreign exchange fluctuates to equate the demand and supply of foreign exchange. Thus, e changes on a frequent basis. Whenever e changes, the IS curve shifts. If