Agricultural data systems remain based upon now obsolete concepts. In particular, the "full-time, family farm" is still organizing concepts for much of the farm data system, and for agricultural policies. Yet farming has clearly bifurcated into: a relatively small number of large farms that produce the majority of the food and fiber; and a large number of small part-time farms that depend mainly on off-farm income for household well-being. Both types are family farms, but they are not the family farms of the past. It is broadly recognized that large farms pose complex challenges for data collection and policy. But small farms are also complex. While small farms may not account for much production they are important for land use issues and for maintaining political support for farm policy. As agricultural policy evolves beyond support commodities it is important to have a better understanding of the heterogeneity of agriculture. This will require more attention to how we define farming, farmers and the objectives of policy.