means of the needs of the final integrator; (4) the innovations of the phase
suppliers; (5) imitation mechanisms.
4. Production of incremental and disruptive innovations. The main
body is made up of incremental innovations due to small variations in
processes, products, or gradual integration in new markets (Garofoli 1989,
p.81). Furthermore, disruptive innovations emerge in some districts,
providing important market advantages (Albors and Molina 2001).
Several models can partially explain the innovative performance of
industrial districts and therefore the existence of the I-district effect: the
cognitive spiral (Becattini 2001), the model of collective inventions (Allen
1983), the knowledge barter and the horizontal diffusion model (von Hippel
1998 and 2002), and the network models of innovation (Cowan 2004).
However, there is no integrated theory of innovation for industrial districts
which allows for a comprehensive explanation of the processes of generating
and diffusing innovation in industrial districts, their impact on local
development processes and the district effect on innovation.
Empirical research of the links between industrial districts and
innovation has contributed important findings regarding these linkages.
Brusco (1975) finds that small metal-mechanical engineering firms around
Bergamo have similar levels of technology to similar large firms, which
contradicts the theory that technological innovation originates exclusively
from internal investment. Russo (1986) shows that the high rates of technical
progress in the ceramic district of Sassuolo cannot be explained by R&D
activities performed in individual firms but rather by the links between the
users and producers of machinery in the ceramic industry. Molina (2002)
finds that knowledge spillovers are important for the innovative dynamic in
the Spanish ceramic district of Castellon. Cainelli and De Liso (2003) find
that the change in added value for innovative and non-innovative firms in
industrial districts is higher than for firms outside districts. Muscio (2006)
finds that innovation in industrial districts is related to the cooperation
between firms and the local division of labour while innovation in non-
district firms is more related to internal and external R&D activities.
Departing from the observation of the high innovative performance of
industrial districts regarding other types of LPS, Boix and Galletto (2008a)
proposed the existence of the I-district effect and contrasted its relationship
with external economies.
3. MEASUREMENT OF INNOVATION AND TYPOLOGY
OF LOCAL PRODUCTION SYSTEMS IN SPAIN
3.1. Measurement of innovation