This thesis aims at showing the necessity of taking product differentiation into account in international trade modelling applied to industrialised countries, especially European. Chapter I is devoted to a survey of literature. In Chapter II, one presents two versions of a theoretical model of monopolistic competition (accounting for strategic interactions or not), which stress the part played by ... [Show full abstract] product differentiation (variety as well as brand image) in the determination of trade. Trade equations are derived from the theoretical model in Chapter III. These equations express that trade flows depend on both traditional factors of demand and relative prices and the two factors of differentiation. It is showed that omitting one differentiation factor results in a modification of theoretical trade price elasticities. In particular, not taking brand image into account induces a decrease in theoretical price elasticities, which might be partly responsible for low estimated price elasticities in empirical literature. Those theoretical results are illustrated by three sets of empirical applications (Chapters IV to VI). Although based on different methods and data (time series, panels, miscellaneous levels of sector aggregation), the estimations lead to clearly significant differentiation factors. Moreover, taking a brand image proxy into account leads to an increase in price elasticities, which become higher than unity, thus entering into the range of possible values for substitution elasticities.
This file contains the beginning of the thesis: title, abstracts, summary, and Chapter 1 (pages 1 to 60).