Briec et al. (2003) Aggregation of directional distance functions and industrial efficiency. J Econ 79:237–261) showed that industrial and structural efficiency are identical in the context of cost aggregation if all firms use the same technology, a single output is produced and constant returns to scale prevail. In this note it is shown that the same is also true if the technology is additive, which is equivalently referred to as independence in production or input non-jointness.
