Introducing Imperfect Competition in CGE Models: Technical Aspects and Implications

This paper considers the technical aspects and the consequences, in terms of simulation results and policy assessment, of introducing imperfect competition in a CGE model. The modifications to the standard CGE framework needed to model imperfect competition in some industries are briefly discussed. Next, the paper discusses whether, how much and why, those changes may affect the qualitative output of a typical simulation experiment. It is argued that technical choices made in designing the model structure may have a significant impact on the model behavior. This is especially evident when the output of the model, under an imperfect competition closure, is compared with that obtained under a standard closure, assuming perfect competition. As an illustration, a scenario of agricultural trade liberalization under alternative market structures is analyzed.Computable general equilibrium models, Imperfect competition, Oligopolistic models, Economies of scale, Empirical industrial organization, Agriculture, Trade liberalization, Trade policy

Platform Competition with Endogenous Multihoming

A model of two-sided market (for credit cards) is introduced and discussed. In this model, agents can join none, one, or more than one platform (multihoming), depending on access prices and the choices made by agents on the opposite market side. Although emerging multihoming patterns are, clearly, one aspect of equilibrium in a two-sided market, this issue has not yet been thoroughly addressed in the literature. This paper provides a general theoretical framework, in which homing partitions are conceived as one aspect of market equilibrium, rather than being set ex-ante, through ad-hoc assumptions. The emergence of a specific equilibrium partition is a consequence of: (1) the structure of costs and benefits, (2) the degree and type of heterogeneity among agents, (3) the intensity of platform competition.Two-sided markets, Network externalities, Standards, Platforms, Multihoming

Price Discrimination and Audience Composition in Advertising-Based Broadcasting

Traditionally, media like TV and radio, but also the Internet, have been characterized by free access (by consumers having the necessary hardware), with services supported through advertising revenues. Profitability in these markets depends on the capability of attracting audience. Strategic choices, however, also depend on the relationship with the dual market for advertising services. In this paper, a model is introduced, which has two distinguishing features. First, the multidimensional nature of competition in media markets is acknowledged, through explicit modeling of vertical and horizontal differentiation. Second, the price of advertising depends on the expected audience composition, not simply on its magnitude. It also depends on the broadcasters' capability of effectively price-discriminate among advertising customers. It is found that market equilibria depend on a number of critical factors: the amount and type of price discrimination in advertising, the correlation between formats and audience composition, the relative profitability of the different market segments, and diseconomies of scale in program quality.Advertising, Media Industries, Broadcasting, Price Discrimination, Television, Radio, Differentiation.

Equilibrium Size in Network with Indirect Network Externalities: a Comment

This commentary critically reviews a recent paper by Baraldi (2004). It shows that results obtained there are not robust, and may mot hold after the introduction of minor changes in the model structure. It is claimed that this is not a technical point, but relates to the fundamental nature of markets with indirect externalities.Network Externalities, Two-Sided Networks

Estimating a Climate Change Damage Function through General Equilibrium Modeling

A Climate Change Damage Function (CCDF) is a reduced form relationship linking macroeconomic aggregates (e.g., potential GDP) to climate indicators (e.g., average temperature levels). This function is used in a variety of studies about climate change impacts and policy analysis. However, despite the fact that this function is key in determining results in many integrated assessment models, it is not typically calibrated in a consistent and rigorous way. This paper presents a novel approach, in which several different impacts of climate change are first assessed by means of a full-fledged computable general equilibrium model of the world economy, then results are interpolated to get a simple relationship of the CCDF type. The estimated CCDF is compared with other popular functions used in the literature, to highlight the possible implications associated with the alternative adoption of this functional relationship.Climate Change, Damage Function, Integrated Assessment, General Equilibrium.

Water Scarcity and Virtual Water Trade in the Mediterranean

Virtual water trade refers to the implicit content of water in the production of goods and services. When trade is undertaken, there is an implicit exchange of water. Furthermore, when water gets scarce, water intensive goods become more expensive to produce and the economy compensates through higher water imports.This paper is about applying the concept of virtual water to the problem of future water scarcity in the Mediterranean area, also induced by the climate change. The aim is assessing to what extent water trade is a viable adaptation option to the problem of water scarcity. To this end, a computable general equilibrium model is extended with satellite data on sectoral water consumption, and used to assess future scenarios of water availability.It is found that virtual trade may curb the negative effect of water scarcity, yet the consequences in terms of income and welfare remain quite significant, especially for some regions.Computable General Equilibrium Models, Water, Virtual Water, Water Scarcity, Climate Change

Platform competition in two-sided markets: the case of payment networks

In this article, we construct a model to study competing payment networks, where networks offer differentiated products in terms of benefits to consumers and merchants. We study market equilibria for a variety of market structures: duopolistic competition and cartel, symmetric and asymmetric networks, and alternative assumptions about multihoming and consumer preferences. We find that competition unambiguously increases consumer and merchant welfare. We extend this analysis to competition among payment networks providing different payment instruments and find similar results.Payment systems ; Competition

Climate Change Assessment and Agriculture in General Equilibrium Models: Alternative Modeling Strategies

Agricultural sectors play a key role in the economics of climate change. Land as an input to agricultural production is one of the most important links between economy and the biosphere, representing a direct projection of human action on the natural environment. Agricultural management practices and cropping patterns have a vast effect on biogeochemical cycles, freshwater availability and soil quality. Agriculture also plays an important role in emitting and storing greenhouse gases. Thus, to consistently investigate climate policy and future pathways for the economic and natural environment, a realistic representation of agricultural land-use is essential. Computable General Equilibrium (CGE) models have increasingly been used to this purpose. CGE models simulate the simultaneous equilibrium in a set of interdependent markets, and are especially suited to analyze agricultural markets from a global perspective. However, modeling agricultural sectors in CGE models is not a trivial task, mainly because of differences in temporal and geographical aggregation scales. The aim of this study is to overview some proposed modeling strategies, by reviewing the available literature and highlighting the different trade-offs involved in the various approaches.Computable General Equilibrium (CGE), Partial Equilibrium (PE), Agriculture, Land Use, Climate Change

Underemployment in a Computable General Equilibrium Model

This paper presents a methodology to account, in a computable general equilibrium model, for the presence of underemployment in an economic system. The methodology is based on the estimation of a matrix, mapping different categories of workers to levels of educational attainment. A procedure is proposed, w hich allows recalculating the matrix after the realization of a simulation with a CGE m odel, when employment levels are varied. In this way, a new matrix is made consistent with the simulation results, identifying a new equilibrium in the labor market, which entails a different combination of unemployment and underemployment

AN INTEGRATED ASSESSMENT MODEL OF ECONOMY-ENERGY-CLIMATE – THE MODEL WIAGEM: A COMMENT

climate change, integrated assessment, computable general equilibrium