Recent discussions on the volatility of agricultural prices have been drawing on factors as low short term elasticities of supply and demand, climatic risk, market uncertainty, central banks monetary policies, trade barriers, biofuel development and, finally, speculation. Much debate has aroused...

Many standard structural models in economics have the property that they induce persistent, partially predictable heteroskedasticity ("volatility clustering") in their key dependent variables, even when their underlying stochastic shock variables are all serially independent and homoskedastic,...