Designing Price Incentives in a Network with Social Interactions

40 Pages Posted: 10 Jan 2014 Last revised: 17 May 2018

See all articles by Maxime Cohen

Maxime Cohen

Desautels Faculty of Management, McGill University

Pavithra Harsha

IBM Research

Date Written: July 1, 2013


The recent ubiquity of social networks allows firms to collect vast amount of data on their customers and on their social interactions. We consider a setting where a monopolist sells an indivisible good to consumers who are embedded in a social network. This an important problem as sellers can use available data to design and send targeted promotions that account for social externality effects and ultimately increase their profits. We capture the interactions among consumers using a broad class of non-linear utility models. This class extends the existing models by explicitly capturing externalities from subsets of agents (communities or groups) and includes several existing models as special cases (e.g., full information version of the triggering model). Assuming complete information about the interactions, we model the optimal pricing problem as a two-stage game. First, the firm designs prices to maximize profits and then consumers choose whether or not to purchase the item. Under positive network externalities, we show the existence of a pure Nash equilibrium that is preferred by both the seller and the buyers. Using duality theory and integer programming techniques, we reformulate the problem into a linear mixed-integer program (MIP). We derive efficient ways to optimally solve the MIP using its linear programming relaxation for two pricing strategies: discriminative and uniform. Finally, we propose two intuitive heuristic algorithms to solve the problem for which we derive worst-case parametric performance bounds. We draw interesting insights on the structure of the optimal prices and the seller's profit. In particular, we quantify the effect on prices when using a non-linear utility model relative to a linear model and identify settings when it is beneficial to offer a price below cost to influential agents. Finally, we extend our model and results to the case where the seller offers incentives (in addition to prices) to solicit actions so as to ensure network externality effects.

Keywords: Pricing, influence models, social networks, integer program, network externalities

Suggested Citation

Cohen, Maxime and Harsha, Pavithra, Designing Price Incentives in a Network with Social Interactions (July 1, 2013). Available at SSRN: or

Maxime Cohen (Contact Author)

Desautels Faculty of Management, McGill University ( email )

1001 Sherbrooke St. W
Montreal, Quebec H3A 1G5

Pavithra Harsha

IBM Research ( email )

T. J. Watson Research Center
Yorktown Heights, NY 10598
United States

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