Chinese firms are experiencing a rapid increase in technological diversification, which is referred to as maintaining their capabilities in multiple technologies. However, the research on the relationship between technological diversification and firm performance is inconclusive. This PhD thesis tries to re-investigate the technological diversification-firm performance relationship from three different perspectives using data on Chinese listed firms from 2003 to 2014. First, the thesis tries to overcome the shortcomings of previous technological diversification research by unpacking technological diversification into explorative and exploitative technological dimensions from the mechanical view and studying their roles in firm performance. The findings suggest that technological diversification that combines explorative and exploitative dimensions is positively related to firm performance. This relationship is conditional on intangible complementary assets and firm type (high or low-tech firms). Second, this thesis tries to investigate the technological diversification-firm performance relationship through an institutional view that has hardly been mentioned in the previous literature. Here it is argued that firms try to use technological diversification as a way to gain legitimacy. In order to do so, firms' technological diversification need to be similar to the industrial norms. The results reveal a positive relationship between firms' conformity in technological diversification and their performance. The results further delineate the boundary conditions that influence this relationship. While environmental dynamism strengthens the conformity-performance relationship, environmental munificence reduces it. Finally, this thesis tries to integrate both a mechanical view and an institutional view of technological diversification and find evidence to support the optimal distinctiveness view that firms should reach a balance between these views. The results reveal a curvilinear (inverted U-shaped) relationship between firms' conformity in technological diversification and their performance. I also test the boundary conditions of this relationship. While firm age strengthens the conformity-performance relationship, state ownership weakens it.

Bien que la créativité soit au cœur du processus d’innovation, peu d’attention a été accordée à la dimension individuelle dans l’analyse de l’activité d’innovation. L’objet de cette thèse est d’étudier le rôle des inventeurs individuels, particulièrement des inventeurs prolifiques, dans la construction des capacités dynamiques des firmes et dans la direction de spécialisation technologique des pays. L’analyse empirique qui sous tend ce travail fait référence aux systèmes d’innovation français et britannique et aux caractéristiques des inventeurs prolifiques de ces deux pays. Nous procédons en premier lieu à une étude statistique des principales caractéristiques des inventeurs français et britanniques. Celle-ci révèle une forte hétérogénéité des inventeurs qui ne se réduit pas à leur productivité en termes de brevets seulement mais se généralise à leur mobilité inter-firmes et à la densité de leur réseau de collaboration. Concernant les sources de cette hétérogénéité, du moins dans sa dimension relative à la production de brevets, notre travail, tout en confirmant les principaux résultats de la littérature sur les déterminants de la productivité des inventeurs, montre de plus que la diversification technologique et la cohérence de la base de connaissances des inventeurs sont parmi les facteurs qui expliquent la différence de productivité des inventeurs tant français que britanniques. Après avoir mis en évidence l’hétérogénéité de la dimension individuelle de l’activité d’innovation, nous étudions la relation entre cette dimension individuelle et le niveau firme et le niveau pays. Notre travail met en évidence, à cet égard, une influence significative de la présence d’inventeurs prolifiques sur la direction de spécialisation technologique des deux pays appréhendée à travers leurs avantages technologiques révélés sectoriels. Par ailleurs, les données de brevets tant de la France que de la Grande Bretagne font apparaitre une relation significative entre le degré de prolificité des inventeurs dans le champ technologique dominant d’une firme et la formation par cette dernière de capacités dynamiques lui permettant de faire face aux évolutions de son environnement technologique. Finalement, en établissant l’hétérogénéité des inventeurs individuels d’une part, et d’autre part, en mettant en évidence une articulation entre la dimension individuelle et les niveaux firmes et pays dans le processus d’innovation, notre travail fournit les éléments d’une représentation qui considère la dimension individuelle comme une composante constitutive des systèmes nationaux d’innovation. / Although creativity is at the heart of the innovation process, little attention has been paid to the individual dimension in the analysis of innovation activity. The purpose of this thesis is to study the role of individual inventors, particularly prolific inventors in building dynamic capabilities of firms and in the direction of technological specialization of countries. The empirical analysis that underlies this work refers to the French and British systems of innovation and to the characteristics of prolific inventors of these two countries. We perform, first, a statistical study of the main characteristics of French and British inventors. The study shows a strong heterogeneity of inventors. This heterogeneity cannot be reduced to their productivity in terms of patents but can be generalized to the inter-firm mobility of inventors and to the density of their collaboration network. Regarding the sources of this heterogeneity, in its dimension relative to the production of patents, our work, while confirming the main findings of the literature on the determinants of the productivity of inventors, shows that technological diversification and coherence of the knowledge base of inventors are also among the factors that explain the difference in the productivity of both French and British inventors. Having highlighted the heterogeneity of the individual dimension of innovation activity, we study the dependence between the individual dimension and the firm and country level of the innovation process. Our work demonstrates, in this regard, a significant effect of the presence of prolific inventors on the direction of technological specialization of both countries in terms of their sectorial revealed technological advantages. Furthermore, patent data of France and the UK reveal a strong relationship between the degree of prolificness in the dominant technological field of firms and their dynamic capabilities.Finally, by establishing the heterogeneity of individual inventors on the one hand and by highlighting a link between the individual dimension and firms and country levels in the innovative process on the other hand, our work provides some elements of a representation which considers individual dimension as a constitutive component of national innovation systems.

Income growth is much more volatile in developing countries than in developed ones. One argument is that weak legal and political institutions exacerbate macroeconomic shocks precipitating the economy into widespread crises. The first chapter of my thesis focuses on sovereign debt crises and discusses how government default in bad times can trigger a liquidity crisis within the economy even in absence of classic foreign penalties. The second chapter takes a complementary perspective and emphasizes the role of sectoral specialization as a source of the higher volatility of emerging markets, much in line with recent empirical evidence. En las ultimas décadas el crecimiento de la renta en los países en desarrollo ha sido mucho más volátil que en los desarrollados. Un explicación es que la debilidad de las instituciones jurídicas y políticas agravan las crisis macroeconómicas precipitando la economía en una crisis generalizada. El primer capítulo de mi tesis se centra en la crisis de la deuda soberana y analiza cómo la insolvencia del gobierno puede desencadenar una crisis de liquidez en la economía, incluso en ausencia de sanciones desde el extranjero. El segundo capítulo adopta una perspectiva complementaria y destaca el papel de la especialización sectorial como fuente de la mayor volatilidad de los mercados emergentes, en consonancia con una reciente evidencia empírica.