Fabrizio Germano

What do the Papers Sell? A Model of Advertising and Media Bias*

We model the market for news as a two-sided market where newspapers sell news to readers who value accuracy and sell space to advertisers who value advert-receptive readers. In this setting, monopolistic newspapers under-report or bias news that sufficiently reduces advertiser profits. Paradoxically, increasing the size of advertising eventually leads competing newspapers to reduce advertiser bias. Nonetheless, advertisers can counter this effect if able to commit to news-sensitive cut-off strategies, potentially inducing as much bias as in the monopoly case. We use these results to explain contrasting historical and recent evidence on commercial bias and influence in the media. Copyright

What Do the Papers Sell

We model the market for news as a two-sided market where newspapers sell news to readers who value accuracy and sell space to advertisers who value advert-receptive readers. We show that monopolistic newspapers under-report or bias news that sufficiently reduces advertiser profits. Newspaper competition generally reduces the impact of advertising. In fact, as the size of advertising grows, newspapers may paradoxically reduce advertiser bias, due to increasing competition for readers. However, advertisers can counter this effect of competition by committing to news-sensitive cut-off strategies, potentially inducing as much under-reporting as in the monopoly case.

On Some Geometry and Equivalence Classes of Normal Form Games

Equivalence classes of normal form games are defined using the geometry of correspondences of standard equilibiurm concepts like correlated, Nash, and robust equilibrium or risk dominance and rationalizability. Resulting equivalence classes are fully characterized and compared across different equilibrium concepts for 2 x 2 games. It is argued that the procedure can lead to broad and game-theoretically meaningful distinctions of games as well as to alternative ways of viewing and testing equilibrium concepts. Larger games are also briefly considered.

Stochastic evolution of rules for playing normal form games

The evolution of boundedly rational rules for playing normal form games is studied within stationary environments of stochastically changing games. Rules are viewed as algorithms prescribing strategies for the different normal form games that arise. It is shown that many of the folk results of evolutionary game theory typically obtained with a fixed game and fixed strategies carry over to the present case. The results are also related to recent experiments on rules and games.

On Commercial Media Bias

Within the spokes model of Chen and Riordan (2007) that allows for non-localized competition among arbitrary numbers of media outlets, we quantify the effect of concentration of ownership on quality and bias of media content. A main result shows that too few commercial outlets, or better, too few separate owners of commercial outlets can lead to substantial bias in equilibrium. Increasing the number of outlets (commercial and non-commercial) tends to bring down this bias; but the strongest effect occurs when the number of owners is increased. Allowing for free entry provides lower bounds on fixed costs above which substantial commercial bias occurs in equilibrium.

Bertrand-Edgeworth Equilibria in Finite Exchange Economies

We introduce a framework for analyzing Bertrand-Edgeworth equilibria in finite Arrow-Debreu exchange economies. A key feature is the way trade takes place. There are two main stages. In the first stage agents simultaneously choose prices and quantities of commodities they want to sell; in the second stage they enter the markets as buyers, sequentially, and choose quantities of commodities they want to buy. We view the framework as providing a realistic, entirely decentralized abstraction of how trade occurs on numerous markets, especially for consumer goods and services, and show that resulting equilibria are Walrasian if and only if initial endowments are already Pareto efficient allocations. Many examples are also considered.

On some collusive and signaling equilibria in ascending auctions for multiple objects

We consider two ascending auctions for multiple objects: the SEAMO (simultaneous English auction for multiple objects) and the the JAMO (Japanese auction for multiple objects). We first derive a (competitive) Perfect Bayesian Equilibrium of the JAMO by exploiting the strategic equivalence between the JAMO and the Survival Auction which consists of a finite sequence of sealed-bid auctions. Then, we prove that many of the (unwanted) collusive or signaling equilibria studied in the literature in the framework of the SEAMO do not have a counterpart in the JAMO. However, it is shown that certain collusive equilibria based on retaliatory strategies do exist in both auctions.

Bounded rationality and correlated equilibria

We study an interactive framework that explicitly allows for nonrational behavior. We do not place any restrictions on how players’ behavior deviates from rationality, but rather, on players’ higher-order beliefs about the frequency of such deviations. We assume that there exists a probability p such that all players believe, with at least probability p, that their opponents play rationally. This, together with the assumption of a common prior, leads to what we call the set of p-rational outcomes, which we define and characterize for arbitrary probability p. We then show that this set varies continuously in p and converges to the set of correlated equilibria as p approaches 1, thus establishing robustness of the correlated equilibrium concept to relaxing rationality and common knowledge of rationality. The p-rational outcomes are easy to compute, also for games of incomplete information. Importantly, they can be applied to observed frequencies of play for arbitrary normal-form games to derive a measure of rationality

Global Nash Convergence of Foster and Young's Regret Testing

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