A dual representation of a technology, e.g., a cost function, may not contain all of the technological information, but it will contain all of the information about input vectors that would be chosen by a cost-minimizing firm. At least this much is clear for deterministic technologies. The main...

Undesirable outputs are often produced together with desirable outputs. This joint production of good and bad outputs brings about a difficulty for productivity measurement. Here we introduce a directional distance function and use it as a component in a new productivity index. This index, as an...