ABSTRACT
Before a theoretical model for the evolution of local industrial clusters can be developed, the economic phenomenon that is called local industrial cluster has to be defined. Only when a clear definition of the research subject is given can a well-structured theory be developed. Most of the concepts in the literature, such as industrial districts, innovative milieux and clusters, have arisen from empirical studies. In the case of industrial districts and clusters, various different definitions can be found (the original discussion of industrial districts is given in Marshall 1920, Book IV, Ch. X, an overview of the concept is given in Rabellotti 1997 for industrial districts and in Braunerhjelm & Carlsson 1999 for clusters), while in the case of innovative milieux, the definitions are more homogenous (the most prominent definition can be found in Camagni 1995). In the industrial districts literature there is quite a dispute over the definition with some authors claiming that the concept of industrial districts has been defined too narrowly (see e.g. Schmitz 1992), while others claim that it has been defined too broadly (see e.g. Dijk 1995).
