Cross-Country Evidence on Output Growth Volatility: Nonstationary Variance and GARCH Models

This paper revisits the issue of conditional volatility in real GDP growth rates for Canada, Japan, the United Kingdom, and the United States. Previous studies find high persistence in the volatility. This paper shows that this finding largely reflects a nonstationary variance. Output growth in the four countries became noticeably less volatile over the past few decades. In this paper, we employ the modified ICSS algorithm to detect structural change in the unconditional variance of output growth. One structural break exists in each of the four countries. We then use generalized autoregressive conditional heteroskedasticity (GARCH) specifications modeling output growth and its volatility with and without the break in volatility. The evidence shows that the time-varying variance falls sharply in Canada, Japan, and the U.K. and disappears in the U.S., excess kurtosis vanishes in Canada, Japan, and the U.S. and drops substantially in the U.K., once we incorporate the break in the variance equation of output for the four countries. That is, the integrated GARCH (IGARCH) effect proves spurious and the GARCH model demonstrates misspecification, if researchers neglect a nonstationary unconditional variance.

The Export Insurance System and Export Supply of Britain

This paper examines whether or not the export insurance subsidy provided by the British government has promoted Britain.s export supply. Unlike previous studies on the effectiveness of export subsidy in export supply, the current study examines the stationarity nature of the concerned variables. The unit root tests show that all concerned variables are integrated of order one. According to Johansen cointegration test, the concerned variables are not cointegrated. The empirical evidences using the first differenced data show that the export subsidy in terms of provision of export insurances by the government is not statistically significant in increasing export supply.