Economies of Scale and Scope in Australian Telecommunications

This paper employs a composite cost function toexamine the cost structure of Australian telephoneservices. The composite cost model combines thelog-quadratic input price structure of the translogmodel with a quadratic structure for multiple outputs. Quadratic output structures permit the measurement ofeconomies of scale, economies of scope, andsubadditivity without prejudging their presence. Model estimates, on Telstra system data from 1926 to1991, show that the production of Australian telephoneservices exhibits economies of scope but no rayeconomies of scale.