Porter (1985) uses the term “value chain” to describe a series of value‐adding activities. This series consists of primary activities, related directly to manufacture, sales and distribution, and secondary activities which support primary activities, such as planning, finance, R&D and human resources. This disaggregation of functions can also be applied to an inter‐firm system, from raw material inputs to consumption (Shank and Govindarajan, 1992; McGuffog and Wadsley, 1999).