Modelling Okun’s Law – Does non-Gaussianity Matter?

From a paper by Tamás Kiss, Hoang Nguyen and Pär Österholm:

“In this paper, we have analysed the relevance of taking non-Gaussianity into account when empirically modelling Okun’s law in Australia, the euro area, the United Kingdom and the United States. Our results based on Bayesian VAR models with stochastic volatility suggest that heavier-than-Gaussian tails find support in some cases. Taking skewness into account is, however, less beneficial in this context considering our baseline sample. Our results confirm that it is important to account for heavy tails in the distribution of macroeconomic variables, an argument put forward by Fagiolo et al. (2008) and Ascari et al. (2015) among others.

It should be noted though that our results to some extent depend on whether data from the corona pandemic are included or not. We believe that including them might be problematic since they should probably be treated as outliers (see the discussion in Carriero et al., 2021). If they nevertheless are treated as regular observations, our analysis indicates that the evidence of non-Gaussianity strengthens. In addition, it can be noted that accounting for non-Gaussianity not only improves the model fit in several cases but it also captures the large swings in the variables without causing large swings in the stochastic volatility.

Apart from the modelling perspective, our analysis has also provided updated international empirical evidence concerning Okun’s law. We find that the dynamic relationship between the variables in all four economies is such that a shock to GDP growth has robustly negative effects on the change in the unemployment rate. This finding is robust to whether we include the period associated with the corona pandemic or not. It confirms Ball et al. (2017) and Ball et al. (2019) who argue that Okun’s law continues to be a robust relationship in empirical macroeconomics. This should be highly relevant information to the central banks of the economies studied here, suggesting that Okun’s law – which has been an important empirical relationship when modelling the economy continues to be useful regardless of modelling choices and time periods.”

Posted by at 9:50 AM

Labels: Macro Demystified


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