| From the second half of the 20th century the industrialized countries have experienced deep transformations in their socio-economic structures. Then services become an important economic activity in modern economies, by raising their contribution in employment and gross domestic product; both magnitudes vary between 60% and 80% in OECD countries.; On the other hand, innovation is a usual topic of investigation in management because it provides competitive advantages to firms, therefore to the economic system. However, research on innovation in services is a relatively new theme that has experienced an important increase from the nineties. Research on innovation in services had been lagging for a long time; an important reason for that delay is the specific characteristics that services have in common. The output that services firms produce is different from manufacturing firms. The main feature is the immateriality, so services are intangible. Then there is the need join production with consumption in space and time. Moreover services are heterogeneous because each act of production becomes a new experience due to active participation of consumers. So services are different. The special characteristics, which overlap all services, become the innovation in a very special process; innovations that carry out services in firms are different from innovations in manufacturing firms. In this sense, it should be recognized that there exists certain difficulty in measuring innovation in services (Evangelista y Sirilli, 1995; Brouwer y Kleinknecht, 1997; Marklund, 1998, 2000; Mohnen y Dagenais, 2002). However there are recent works attempting to give a solution to this problem.; This doctoral thesis analyses innovation strategy carried out by services firms. Thus firstly we classify services firms according to productive strategies. Subsequently we identify innovation patterns in these firms. After that we analyse incidence of innovation in performance firms. We carried out an analysis cluster to achieve the fast and second objective, and we outlined fit analysis using the methodology of ideal profile fit. This analysis allows us to discover the effect that productive and innovative strategies have on firm' performances.; In conclusion, with this thesis we contribute to the understanding of the innovative behaviour of services firms, by providing evidence that strengthens theoretical arguments, which are the base in this investigation. |