Essais en microéconomie appliquée

This thesis includes three essays in applied microeconomics. Using learning and network effects models, we study agents’ behavior in various environments through three chapters. The first chapter examines natural resource exploitation under uncertainty with learning and heterogeneous priors. In the second chapter, we examine the problem of research Foundation concerned with finding good quality researchers for today and the future. The third chapter studies the Multi-level marketing organizations. The first chapter is entitled "Renewable Resource Consumption in a Learning Environment with Heterogeneous beliefs". This work uses a learning model with heterogeneity of beliefs to study natural resources consumption under uncertainty. Following Koulovatianos et al (2009), we distinguish two types of learning process: adaptive learning and learning. I find that learning decreases the total consumption of the resource in comparison with adaptive learning. However, individually and under some conditions, some exploiters could consume more in learning than in adaptive learning. In learning, the exploiter faces two kinds of incentive to invest in the resource: self-incentive which is always positive and heterogeneity incentive which may be negative. The effect of learning on individual consumption depends on the sign and the extent of the heterogeneity incentive. Using absolute change and relative change of consumption due to a change in beliefs, we find that the exploiters tend to converge to a common behaviour. The second chapter is entitled "A perpetual Search for Talent across Overlapping Generations". We use a dynamic discrete time model with overlapping generations to study how a research Fund should optimally rank and select which researchers to give a grant. The optimal decision rule depends on both the perceived quality of researchers based on past success histories and on age. Between two researchers of equal perceived qualities the Fund should select the youngest. This work contributes to the understanding of the bandit problems sometime known to be untractable and pspace-hard. Here, instead of looking for an index characterization, we propose to rank or eliminate progressively the researchers by comparing them two by two. The third chapter is entitled "Paradox about the Multi-Level Marketing". Over the past 50 years, the Multi-level Marketing (MLM) has become an important business strategy. vi MLM is a marketing method in which independent distributors of a product get profits not only from their own sales, but also from recruiting other distributors. According to the promoters of this organization, the purpose of the business and the will of the distributors are to sell the product and not to set up a scam. The question is the following: if the real intention is to sell, why does a distributor recruit other distributors who will become his competitors? It is well known in classical industrial organization that people avoid competition as well as possible. Why is it not the case in the MLM organization? We explain this paradox by the particular economic structure of the MLM. Distributor could not sell enough if he did not recruit. Recruiting provides a price leading power and allows to sell more and make more profit (in some respect). Moreover, the MLM is similar to the multi-sided market structure a la Rochet and Tirole (2003, 2006) and Weyl (2010). There is network effect between recruitment and selling activity. Thus, the extent of the paradox can also be explained by the different commissions set by the MLM promoters.

Keyphrases: Learning, Bandit problems, Multi-level marketing, Two-sided market