Governments in OECD countries intervene in agriculture with a view to achieving a wide range of economic and social objectives. One of the most cited reasons for intervention is to improve the income position of farm households. Although largely a legacy of concern with the economic plight of farm families in earlier times, the belief that government intervention is needed to ensure adequate income levels for farm families is wide-spread. References to the level, variability or distribution of farm household income can be found in framework documents, legislation and political speeches, but such references are usually quite imprecise concerning the target populations or the target levels of the variables mentioned. Although there is significant government intervention leading to high levels of support and protection in many countries, it is difficult to identify which policies are designed and put in place to address income problems specifically. This creates considerable difficulty in programme evaluation, difficulties that are compounded by a lack of appropriate data.