A Theory of Strategic Diffusion

The important role of friends, neighbors and colleagues in shaping individual choices has been brought out in a number of studies over the years. The presence of significant 'local' influence in shaping individual behavior suggests that firms, governments and developmental agencies should explicitly incorporate it in the design of their marketing and developmental strategies. This paper develops a framework for the study of optimal strategies in the presence of social interaction. We focus on the case of a single player who exerts costly effort to get a set of individuals � engaged in social interaction � to choose a certain action. Our formulation allows for different types of social interaction and also allows for the player to have incomplete information concerning the connections among individuals. We first show that incorporating information on social interaction can have large effects on the profits of a player. Then, we establish that an increase in the level and dispersion of social interaction can raise or lower the optimal strategy and profits of the player, depending on the content of the interaction. Finally, we study the value of social network information for the player and find that it depends on the dispersion in social connections. The economic interest of these results is illustrated via a discussion of two economic applications: advertising in the presence of word of mouth communication and seeding a network.

Endogenous Trading Networks

We investigate the effects of a class of trading protocols on the architecture and efficiency properties of endogenously formed trading networks. In our model, the opportunity to sell valuable objects occurs randomly to different individuals. A sale can only be realized if two individuals are connected, directly or indirectly, but forming and maintaining a trading relation is a costly investment. When the outcome of trading is efficient and provides no intermediation rents, a tension between equilibrium and efficient networks emerges when the cost of forming a link is at an intermediate level. There are two types of inefficiencies. Either all equilibrium networks are under- connected when compared to efficient networks, or a multiplicity of equilibriam may exist and agents may fail to coordinate on the efficient equilibrium network

Bilateral Trading in Networks

We study an incomplete-information model of sequential bargaining for a single object, with the novel feature that agents are located in a network. In each round of trade, the current owner of the object either consumes it or makes a take-it-or-leave-it offer to some connected trader. Traders may buy in order to consume or to resale to others. We show that the equilibrium price dynamics is non-monotone and that traders that intermediate the object arise endogenously and attain a pro t. We also provide insights on how traders' equilibrium payoffs depend on their location in the network.

Network Multipliers and the Optimality of Indirect Communication

We study the problem of a firm M which wishes to inform a community of individuals about its product. Information travels within the community because of the social interactions between individuals. Our interest is in understanding how the firm can incorporate the network of social interactions in the design of its communication strategy. We study a model of undirected networks and start by showing that social interactions appear in the payoff of the firm in the form of a network multiplier. We establish that the network multiplier is an increasing function of both the mean and the variance in the distribution of connections of the network. This implies in particular that denser and more dispersed degree distributions are better for the firm. We then show that the degree distribution of the neighbour first order dominates the degree distribution of a node at large and so it is always better for a firm to use indirect communication, i.e., viz. picking the neighbour of a node rather than a node itself as the target of communication. Finally, we show that the advantages of indirect communication are increasing with dispersion in the degree distribution.

A Theory of Strategic Diffusion

The important role of friends, neighbors and colleagues in shaping individual choices has been brought out in a number of studies over the years. The presence of significant ‘local’ influence in shaping individual behavior suggests that firms, governments and developmental agencies should explicitly incorporate it in the design of their marketing and developmental strategies. This paper develops a framework for the study of optimal strategies in the presence of social interaction. We focus on the case of a single player who exerts costly effort to get a set of individuals – engaged in social interaction – to choose a certain action. Our formulation allows for different types of social interaction (ranging from sharing of information to direct adoption externalities) and also allows for the player to have incomplete information concerning the connections among individuals. The analysis starts by showing that incorporating information on social interaction can have large effects on the profits of a player. We then show that an increase in the level and dispersion of social interaction can raise or lower the optimal strategy and profits of the player, depending on the content of the interaction. We then study the value of social network information for the player and find that it depends on the dispersion in social connections. The economic interest of these results is illustrated via a discussion of two economic applications: advertising in the presence of word of mouth communication and seeding a network.Social Interaction, Seeding the Network, Word of Mouth Communication, Diffusion Strategy

The Law of the Few

The law of the few refers to the following empirical phenomenon: in social groups a very small subset of individuals invests in collecting information while the rest of the group invests in forming connections with this select few. In many instances, there are no observable differences in characteristics between those who invest in information and those who invest in forming connections. This paper shows that the law of few naturally emerges in environments with identical rational agents. We develop a strategic game in which players have the opportunity to invest in collecting information as well as in investing in bilateral connections with others. We find that every strict equilibrium of this game exhibits the �law of the few�. We also show that this pattern of social differentiations is efficient in some cases.

Statistical and Economic Evaluation of Time Series Models for Forecasting Arrivals at Call Centers

Call centers' managers are interested in obtaining accurate point and distributional forecasts of call arrivals in order to achieve an optimal balance between service quality and operating costs. We present a strategy for selecting forecast models of call arrivals which is based on three pillars: (i) flexibility of the loss function; (ii) statistical evaluation of forecast accuracy; (iii) economic evaluation of forecast performance using money metrics. We implement fourteen time series models and seven forecast combination schemes on three series of daily call arrivals. Although we focus mainly on point forecasts, we also analyze density forecast evaluation. We show that second moments modeling is important both for point and density forecasting and that the simple Seasonal Random Walk model is always outperformed by more general specifications. Our results suggest that call center managers should invest in the use of forecast models which describe both first and second moments of call arrivals

Network Formation with Heterogeneous Players

This paper studies a connections model of network formation in which players are heterogeneous with respect to values as well as the cost of forming links. We start by showing that value heterogeneity is important in determining the level of connectedness of a network, while cost heterogeneity is important in shaping both the level of connectedness as well as the architecture of individual components in a network. We then explore the role of cost heterogeneity in a society which is divided into distinct groups and intra-group links are cheaper as compared to inter-group links. Here we find that inter-connected stars with locally central players are socially efficient as well as dynamically stable. We interpret our results as saying that centrality, center-sponsorship and small diameter are robust features of networks.

A Model of Strategic Targeted Advertising

We study a simultaneous move game of targeted advertising and pricing in a market with various consumer segments. In this setting we explore the implications of market segmentation on firm competitiveness. If firms are unable to target their ads on different consumer segments, a unique zero-profit equilibrium exists. By contrast, if firms employ targeted advertising, they can obtain positive profits. In equilibrium firms price very aggressively when they address the most profitable segment, quite gently when they target their ads on the least profitable segment and moderately aggressive when they advertise in the entire market.segmentation, targeted advertising, oligopoly, price dispersion, price discrimination

Strategic Information Transmission in Networks

We introduce a tractable model of cheap talk among players located on networks. In our model, a player can send a message to another player if and only if he is linked to him. We derive a sharp equilibrium and welfare characterization which reveals two basic insights. In equilibrium, the willingness of a player to communicate with a neighbor decreases with the number of opponents who communicate with the neighbor. The ex-ante equilibrium welfare of every player increases not only with the number of truthful reports transmitted in the network, but also when truthful reports are more evenly distributed across players. We apply our findings to the analysis of homophily in communities, to organization design, and to the study of endogenous network formation. Communication across communities decreases as communities become larger, and communication may be asymmetric: From large communities to small ones. In our set up, fully decentralized organizations maximize all players� welfare. Further, decentralized networks, where information may flow asymmetrically, endogenously form in equilibrium. Finally, we introduce the possibility of public communication in networks, and identify conditions under which public communication Pareto dominates private communication.