In the knowledge-based economy, innovation is considered essential in order to achieve survival and growth in organizations. On the other hand, knowledge management is currently understood as one of the keys to innovation process. Both factors are generally admitted as generators of competitive advantage in organizations. Specifically, activities on R&D&I and those that generate internal knowledge have a positive influence in innovation results. This paper examines this effect and if it is similar or not is what we aimed to quantify in this paper. We focus on the impact that proportion of knowledge workers, the R&D&I investment, the amounts destined for ICTs and training for innovation have on the variation of tangible and intangibles returns for the sector of high and medium technology in Spain. To do this, we have performed an empirical analysis on the results of questionnaires about innovation in enterprises in Spain, collected by the National Statistics Institute. First, using clusters methodology, the behavior of these enterprises regarding knowledge management is identified. Then, using SEM methodology, we performed, for each cluster, the study about cause-effect relationships among constructs defined through variables, setting its type and quantification. The cluster analysis results in four groups in which cluster number 1 and 3 presents the best performance in innovation with differentiating nuances among them, while clusters 2 and 4 obtained divergent results to a similar innovative effort. However, the results of SEM analysis for each cluster show that, in all cases, knowledge workers are those that affect innovation performance most, regardless of the level of investment, and that there is a strong correlation between knowledge workers and investment in knowledge generation. The main findings reached is that Spanish high and medium technology companies improve their innovation performance investing in internal knowledge generation measures, specially, in terms of R&D activities, and underinvest in external ones. This, and the strong correlation between knowledge workers and the set of activities that promote the knowledge generation, should be taken into account by managers of companies, when making decisions about their investments for innovation, since they are key for improving their opportunities in the global market.
 Carneiro, «How does knowledge management influence innovation and competitiveness?» Journal of Knowledge management, vol. 4, nº 2, pp. 87-98, 2002.
 M. Alavi and D. E. Leidner, «Review: Knowledge Management and Knowledge Management Systems: Conceptual Foundations and Research Issues» MIS Quarterly, vol. 25, nº 1, pp. 107-136, 2001.
 T. Davenport and L. Prusak, Working Knowledge: How Organizations Manage What They Know, Boston, M.A.: Harvard Business Press, 1998.
 R. Hall, «A framework linking intangible resources and capabilities to sustainable competitive advantage,» Strategic management journal, vol. 14, nº 8, pp. 607-618, 2006.
 R. Daft, «Bureaucratic versus non Bureaucratic structure and the process of innovation and change,» de Research in the Sociology of Organisations, Greenwich, JAI press, 1982.
 K. Knight, «A descriptive model of the intra-firm innovation process,» The Journal of Business, vol. 40, nº 4, pp. 478-496, 1967.
 I. Nonaka and H. Takeuchi, The Knowledge Creating Company: How Japanese Companies Create the Dynamics of Innovation, New York, NY.: Oxford University Press, 1995.
 L. Argote, Organizational Learning: Creating, Retaining, and Transferring Knowledge, Boston, M.A.: Kluwer Academic Publishers, 1999.
 J. Darroch and R. McNaughton, «Examining the link between knowledge and management practices and types of innovation,» Journal of Intellectual Capital, vol. 3, nº 3, p. 210, 2005.
 R. Grant, «Toward a Knowledge-Based Theory of the Firm,» Strategic Management Journal, vol. 17, pp. 11-154, 2002.
 J. Huang and Y. Li, «The mediating effect of knowledge management on social interaction and innovation performance,» International Journal of Manpower, vol. 30, nº 3, pp. 285-301, 2009.
 U. Cantner, K. Joel and T. Schmidt, «The use of knowledge management by German Innovators,» Journal of Knowledge Management, vol. 12, nº 6, pp. 187-203, 2009.
 L. Earl, « Knowledge Management Practices Survey in Canada 2002,» Nº 7, 2003.
 K. Goffin and R. Mitchell, Innovation Management: Strategy and Implementation using the pentathlon framework, 2 ed., New York, N.Y.: Palgrave MacMillan, 2005.
 L. Tin, «Measuring innovation performance,» 2005. (Online). Available: https://www.nlb.gov.sg/Portals/0/Docs/Research/InnovationPerformance.pdf. (Last access: 10 11 2015).
 R. Grant and C. Baden-Fuller, «A knowledge accessing theory of strategic alliances,» Journal of Management Studies, vol. 41, nº 1, pp. 61-79, 2004.
 M. Zack, «Managing Codified Knowledge,» Sloan Management Review, vol. Summer, pp. 45-48, 1999.
 W. Cohen and D. Levinthal, «Absorptive capacity: A New Learning Perspective on Learning and Innovation,» Administrative Science Quarterly, vol. 35, pp. 128-152, 1990.
 U. Flick, An introduction to qualitative research, 4 ed., Londres: Sage Publications, 2009.
 J. Gill and P. Johnson, Research methods for managers, 4 ed., Londres: Sage Publications, 2010.
 INE (Instituto Nacional de Estadística), Encuesta sobre Innovación en las Empresas 2010, Madrid, 2012.
 M. Ruiz, A. Pardo and R. San Martin, «Modelos de ecuaciones estructurales,» Papeles del Psicólogo, vol. 31, nº 1, pp. 34-45, 2010.
 L. Williams, J. Cote and M. R. Buckley, «Lack of method variance in self-reported affect and perceptions at work: reality or artefact?,» Journal of Applied Psychology, vol. 74, nº 3, p. 462.468, 1989.
 J. F. Hair, R. E. Anderson, R. Tatham and W. Black, Multivariate data analysis, Englewood Cliffs, NJ: Prentice Hall, 1995.
 A. Page, Hacia un modelo causal del rendimiento académico, Madrid: CIDE, 1990.
 R. Bizquerra, Métodos de Investigación Educativa, México: CEAC, 1989.
 K. Jöreskog, «A general approach to confirmatory maximum likelhood factor analysis with addendum,» de Advances in factor analysis and structural equation model, K. J. &. D. Sörbom, Ed., Cambridge, Abt Books, 1979.
 R. P. Bagozzi and Y. Yi, «On the evaluation of structural equation models,» Journal of the Academy of Marketing Science, vol. 1, nº 16, pp. 74-94, 1988.
 P. M. Bentler, «Comparative fit indexes in structural models,» Psychological Bulletin, nº 107, pp. 238-246, 1990.
 L. Hu and P. Bentler, «Cutoff criteria for fit indexes in covariance structure analysis: Conventional criteria versus new alternatives,» Structural Equation Modeling, vol. 6, nº 1, pp. 1-55, 1999.
 S. Weelwright and K. Clarck, Revolutionizing Product Development- Quantum Leaps in Speed, Efficiency, and Quality, New York; N.Y.: The Free Press, 1992.
 J. Alegre, K. Sengupta y R. Lapiedra, «Knowledge Management and Innovation performance in a high-tech SMEs industry» International Small Business Journal, vol. 31, pp. 454-470, 2011.