by Jan-Philipp Dueber, University of Kent. Discussion paper KDPE 1811, August 2018.
Time-varying volatility plays a crucial role in understanding business cycles in emerging market economies. There is now plentiful empirical evidence that volatility as measured by the standard deviation in macroeconomic data is time-varying and strongly countercyclical. Volatility increases during an economic recession and becomes lower during an economic boom.
In addition, we observe that standard open-economy macroeconomic models widely used for business cycle analysis fail to address the specific characteristics of many emerging market economies. In emerging market economies the net export to output ratio is typically negatively correlated with output i.e. it is countercyclical. However, standard models predict a near perfect positive correlation between the two. Besides that, emerging market economies show a higher fluctuation in consumption data than in data on output. Standard models, however, predict a higher fluctuation in output than consumption. These models are therefore overemphasizing the role of consumption smoothing.
This work is motivated by the above empirical observations. We augment a standard small-open economy model and introduce time-varying volatility to the interest rate and total factor productivity. In our model the interest rate and total factor productivity automatically turn more volatile when the economy becomes more indebted or when output declines in response to a negative total factor productivity shock. Once we introduce time-varying volatility into a standard open-economy model, the model becomes able to significantly better match emerging market economy data. After the introduction of a time-varying interest rate and total factor productivity we are able to present a model where net exports are strongly negatively correlated with output and consumption shows a higher variation than output as observed in the data. By choosing different parameter values for the time-varying volatility the model is able to characterize both, emerging market and developed economies, or an economy that is in transition to a developed economy.
Although we are not the first to address the problems of macroeconomic models for emerging market economies, our approach is especially simple and does not rely on shocks to the permanent component of total factor productivity or to shocks in the level of the interest rate. Compared to other research in this area our approach only requires one source of external variation, the widely used shock to total factor productivity. From a policy point of view our model can be especially useful for economists and policy makers in emerging market economies as our model now better fits the economic cycle in those countries.
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