Expliquer les évolutions des cours des matières premières agricoles : À l’impossible, nul n’est tenu !

How to explain the recent developments in the prices of agricultural raw materials? This article tries to trace the chronology of events and identify the mechanisms by which factors of change in agricultural prices act. From this analysis of temporal and causal effects an important lesson emerges, namely the difficulty if not the impossibility to isolate the responsibility of a particular determinant, even more to quantify it. Hence also the need to develop the economic analysis of agricultural prices, of their trends and determinants, including through the use of quantitative structural models, i.e., models that explicitly derived suplly and demand functions from behaviours of private and public actors.