A production unit carries out an economic activity under the control and responsibility of an institutional unit using inputs of labour, capital and goods and services to produce outputs of goods and services. Enterprises can be very heterogeneous if they have several secondary activities that are quite different from their principal activities. In order to obtain groups of producers whose activities are more homogeneous, enterprises are partitioned into smaller and more homogeneous units of production like local units, kind-of-activity units, and establishments.