The aim of the study is to measure the impact of the 1992 reform of the Common Agricultural Policy (CAP) on arable crop yields in the European Union (EU), and more specifically to quantify the impact that the introduction of compensatory area payments had on yields. The CAP reform in May 1992 consisted largely in reducing support prices and offsetting the ensuing loss of income with direct payments based on factors of production, i.e. acreage in the case of COP (cereal, oilseed and protein) crops.