1 THE EFFECTS OF REGIONAL SCIENTIFIC OPPORTUNITIES IN SCIENCE- TECHNOLOGY FLOWS: EVIDENCE FROM SCIENTIFIC LITERATURE CITED IN FIRMS PATENT DATA. Manuel Acosta Daniel Coronado* Departamento de Economa General University of CÆdiz SPAIN manuel.acosta@uca.es daniel.coronado@uca.es Abstract: The objective of this study is to advance, from a quantitative point of view, in the knowledge of the science-technology flows from a regional perspective. The methodology utilised in this study is based on the scientific citations in patent documents (NPC), and has previously only been applied in national contexts. After describing the spatial and sectorial patterns, we propose to identify the explanatory factors by modelling the citations in patent documents (taking this variable as a proxy for the science-technology flows) in function of a set of three blocks of explanatory factors: businesses (microeconomic variables), industries (sectorial variables) and spatial contexts (variables of location and of the scientific environment). The model is of the microeconomic type and the most appropriate formulation, given the nature of the endogenous variable, is that of the counted data type. The statistical data originate from a comprehensive review of the 1,643 patents applied for by 1,129 companies, and published during the years 1998 to 2001, both inclusive. The basic source of data is the domestic patent documents themselves, published by the Spanish Office of Patents and Trade Marks. This information has been tabulated to obtain regional indicators of science-technology flows and the variables for inclusion in the model. The statistical treatment of the primary information and the operation of the model provide us with objective data that may serve as an additional point of reference for reflecting on the incidence on the regional productive system of specific measures taken under regional scientific policies. Key words: Science-technology flows, regional spillovers, patent data. * The authors are members of the Regional Economy research group. CentrA (Junta de Andaluca).