This article provides a theoretical framework related to Data Envelopment Analysis (DEA) in which an analytical relationship among eight different efficiency concepts is defined and explored in terms of production and cost analyses. This article extends the theoretical basis into the measurement...

This article discusses whether the Japanese government should break up NTT (Nippon Telegraph & Telephone) in 1995, as the U.S. federal government compelled AT&T (American Telephone & Telegram) to break itself into toll and local telephone companies in 1984. The divestiture of NTT has long been a...

This article discusses the concept of RTS (Returns To Scale) in the framework of DEA (Data Envelopment Analysis) production and cost analyses, focusing on an occurrence of multiple solutions and how to deal with such a difficulty. Dual relationships between production-based and cost-based RTS...