Contest with Attack and Defence: Does Negative Campaigning Increase or Decrease Voters' Turnout?

We present a general model of two players contest with two types of efforts. Contrary to the classical models of contest, where each player chooses a unique effort, and where the outcome depends on the efforts of all the players, contestants are allowed to reduce the effort of the opponent. Defence increases one's chance of winning while attack annihilates the defence of the opponent. This model has many applications like political campaigning, wars, competition among lobbies, job promotion competitions, or sport contests. We study the general model of contest with attacks and defence and propose an application to negative political campaigns, where two candidates arbitrate between disparaging their opponent or enhancing their own image. We propose sufficient conditions for the existence and uniqueness of a symmetric Nash equilibrium of the contest game. In the application, we contribute to the empirically debated question dealing with the effect of attack on voters turnout, and show that the conclusion depends on the distribution of voters sensitivity to defence and attack. Furthermore, contrary to the literature, we show that an underdog candidate may be less aggressive than his opponent.Contest, Rent-seeking, Negative Campaigning, Turnout, Sabotage.

Knowledge Accumulation within an Organization

We develop a simple model of task allocation for knowledge workers over their career within an organization. The human capital theory initiated by Becker (1962, 1964) has o¤ered a rich analysis of an individuals life cycle investment in human capital. One of the main result of this literature states that human capital investments are undertaken at the early stage of the career because workers have then a longer period of time over which they can bene…t from the return of their investments. In this paper, we consider a knowledge accumulation problem within an organization that cannot prevent the worker from quitting and using the knowledge outside the organization. In the …rst best situation, we show a similar result as in the human capital theory, i.e. the share of time allocated to knowledge creation tasks decreases over time. We then ask how this pattern is a¤ected when the knowledge worker can leave the organization and bene…t from this knowledge outside the organization. In this case, we obtain the novel result that the time path of the fraction of working time allocated to knowledge creation tasks is non-monotone. This fraction is highest at the early career stage, falls gradually, then rises again, before falling …nally toward zero. We also show that an increase in the …rm-speci…city of knowledge can increase or decrease the life-time income of the knowledge worker.

On the (In-)Efficiency of Unanimity in Multilateral Bargaining with Endogenous Recognition

In this paper, we study the (symmetric) equilibria of a model of multilateral bar- gaining where players are heterogeneous regarding their time preferences, and make costly efforts at the beginning of the process in order to inuence their probabilities of being the proposer for all stages of the negotiation process. We analyse whether the optimality of the unanimity rule (as the voting rule minimizing the social cost resulting from the agents' willingness to buy inuence) characterised in Yildirim (2007) extends to the present situation. In the case of weakly heterogeneous agents, we show that k-majority rules may actually become strictly optimal. Then we provide numerical ex- amples that suggest that there are situations where each type of voting rule (unanimity and strict k-majority) may be socially optimal.

Drought and Civil War in Sub-Saharan Africa

We show that civil war is strongly related to drought in sub-Saharan Africa. We consider the eect of variations in the Palmer Drought Severity Index (Palmer 1965) - a cumulative index that combines precipitation, temperature and the local characteristics of the soil - on the risk of civil war. While the recent, contentious debate on the link between climate and civil war has mainly focused on precipitation and temperature, without obtaining converging results, the Palmer index describes social exposure to water stress in a more ecient way. We show that it is a key factor of civil war in sub-Saharan Africa and that this result is robust to various specications and passes a series of sensitivity tests. Also, our results indicate that agriculture, ethnic diversity and institutional quality are important factors to link climate and civil war.

Drought and Civil War in Sub-Saharan Africa

In this paper, we show that drought has a positive effect on the incidence of civil war over the 1945-2005 period in Sub-Saharan Africa. We use the Palmer Drought Severity Index which is a richer measurement of drought than the measures used in the literature (rainfall and temperature) as it measures the accumulation of water in the soil in taking into account the temperature and the geological characteristics of the soil. We show that the risk of civil war increases by more than 42% from a “normal” climate to an “extremely drought” climate. Surprisingly, only 2.5% of this effect is channeled through economic growth.Climate Change, Drought, Civil War

Collective Reputation, Entry and Minimum Safety Standard

This article deals with the issue of entry into an industry where firms share a collective reputation. First, we show that free entry is not socially optimal; there is a need for regulation through the imposition of a minimum quality standard. Second, we argue that a minimum quality standard can induce firms to enter the market. Contrary to conventional wisdom, a minimum quality standard should not always be considered as a barrier to entry.Collective Reputation, Entry, Minimum Quality Standard, Institutional and Behavioral Economics,

Civil War in a Globalized World: Diplomacy and Trade

We consider the impact of diplomatic intervention in civil wars on international trade. Using a large data set over the period 1948-2005, we obtain two striking results: (i) diplomatic intervention has a positive effect on trade for the country in which the civil war occurs (target country); and (ii) bilateral trade between the target and intervening country does not increase more than trade between the target country and the other countries. We argue that intervention induces an enhancement of trade-promoting capital in the target country and show that diplomatic intervention has a positive effect on institutional quality in the target country.

Political Cycles : The Opposition Advantage

We propose a two dimensional infinite horizon model of public consumption in which investments are decided by a winner-take-all election. Investments in the two public goods create a linkage across periods and parties have different specialities. We show that the incumbent party vote share decreases the longer it stays in power. Parties chances of winning do not converge and, when the median voter is moderate enough, no party can maintain itself in power for ever. Finally, the more parties are specialized and the more public policies have long-term effects, the more political cycles are likely to occur.Cycles, Alternation, Public goods, Advantage, Opposition

Voting Rules in Bargaining with Costly Persistent Recognition

In this paper, we consider a model of multilateral bargaining where homogeneous agents may exert e¤ort before negotiations in order to inuence their chances to become the proposer. E¤ort levels have a permanent effect on the recognition process (persistent recognition). We prove two main results. First, all voting rules are equivalent (that is, they yield the same social cost) when recognition becomes persistent. Secondly, an equilibrium may fail to exist, because players may have more incentives to reduce their e¤ort level (in order to be included in winning coalitions) than to increase it (in order to increase their proposal power). Both results di¤er greatly from the case where recognition is transitory: Yildirim (2007) shows that una- nimity is the unique strictly optimal rule, and that an equilibrium always exists (under mild assumptions) in such a setting. Moreover, our second conclusion is quite di¤erent from the one obtained in most of the existing literature on bargaining (which assumes an exogenous recognition process), where it is generally considered that it is always in an agents best interest to have a proposal power as high as possible.

When does universal peace prevail? Secession and group formation in rent seeking contests and policy conflicts

This paper analyzes secession and group formation in a general model of contest inspired by Esteban and Ray (1999). This model encompasses as special cases rent seeking contests and policy conflicts, where agents lobby over the choice of a policy in a one-dimensional policy space. We show that in both models the grand coalition is the efficient coalition structure and agents are always better off in the grand coalition than in a symmetric coalition structure. Individual agents (in the rent seeking contest) and extremists (in the policy conflict) only have an incentive to secede when they anticipate that their secession will not be followed by additional secessions. Incentives to secede are lower when agents cooperate inside groups. The grand coalition emerges as the unique subgame perfect equilibrium outcome of a sequential game of coalition formation in rent seeking contests