Asymmetric relationship between global and national factors and domestic food prices : evidence from Turkey with novel nonlinear approaches

This study investigates the asymmetric relationship between global and national factors and domestic food prices in Turkey, considering the recent rapid and continuous increase in domestic food prices. In this context, six global and three national explanatory variables were included, and monthly data for the period from January 2004 to June 2021 were used. In addition, novel nonlinear time-series econometric approaches, such as wavelet coherence, Granger causality in quantiles, and quantile-on-quantile regression, were applied for examination at different times, frequencies, and quantiles. Moreover, the Toda-Yamamoto (TY) causality test and quantile regression (QR) approach were used for robustness checks. The empirical results revealed that (i) there is a significant relationship between domestic food prices and explanatory variables at different times and frequencies; (ii) a causal relationship exists in most quantiles, excluding the lowest quantile, some middle quantiles, and the highest quantile for some variables; (iii) the power of the effect of the explanatory variables on domestic food prices varies according to the quantiles; and (iv) the results were validated by the TY causality test and QR, which show that the results were robust. Overall, the empirical results reveal that global and national factors have an asymmetric relationship with domestic food prices, highlighting the effects of fluctuations in global and national variables on domestic food prices. Thus, the results imply that Turkish policymakers should consider the asymmetric effects of global and national factors on domestic food prices at different times, frequencies, and quantiles.