An Empirical Model of Search with Vertically Differentiated Products

This paper presents a non-sequential search model that allows for vertical product differentiation. In the unique symmetric equilibrium firms with different characteristics draw utilities from a common utility distribution, resulting in asymmetric price distributions. The model therefore provides a theoretical rationale for explaining price dispersion as a result of quality differences and search frictions together. More specifically, the model can explain the frequent and asymmetric price changes reported in several empirical papers, but also why some firms have persistently higher prices than others. Using the equilibrium conditions derived from the model, we show how to estimate search costs by maximum likelihood using only prices. The method is applied to a data set of prices for grocery items from supermarkets in the UK. Estimates reveal that most of the observed price variation can be explained by supermarket heterogeneity and that the estimated amount of search is low in this market. We show that ignoring vertical product differentiation results in an overestimation of search costs. Moreover, estimated search costs using a basket of organic items are on average higher than that of a similar non-organic basket. We also simulate how changes in search costs will affect behavior of stores and consumers.consumer search, product differentiation, price dispersion, structural estimation

Estimate of Search Cost Frictions in the British Electricity Market

This paper studies consumer search and pricing behaviour in the British domestic electricity market following its opening to competition in 1999. We develop a sequential search model in which an incumbent and an entrant group compete for consumers who find it costly to obtain information on prices other than from their current supplier. We use a large data set on prices and input costs to structurally estimate the model. Our estimates indicate that consumer search costs must be relatively high in order to rationalize observed pricing patterns. We confront our estimates with observed switching behaviour and find they match well.electricity, consumer search, price competition

Comparison Sites

Web search technologies are fundamental tools to easily navigate through the huge amount of information available in the Internet. One particular type of search technologies are the so- called shopbots, or comparison sites. The emergence of Internet shopbots and their implications for price competition and market efficiency are the focus of this chapter. We develop a simple model where a price comparison site tries to attract (possibly vertically and horizontally differentiated) online retailers on the one hand, and consumers on the other hand. The analysis of the model reveals that differentiation among the products of the retailers as well as their ability to price discriminate between on- and off-comparison-site consumers play a critical role. When products are homogeneous, if online retailers cannot charge different on- and off-the-comparison- site prices, then the comparison site has incentives to charge fees so high that some firms are excluded, which generates price dispersion and an inefficient outcome. By contrast, when on- and off-comparison-site prices can be different, the comparison site attracts all the players to the platform and the allocation is efficient. A similar result obtains when products are horizontally differentiated. In that case, the comparison site becomes an aggregator of product information and no matter whether firms can price discriminate or not, the comparison site attracts all the players to the platform and an efficient outcome ensues. We argue that the lack of vertical product differentiation may also be critical for this efficiency result. In fact, we show that when quality differences are large, the comparison site may find it profitable to charge fees such that low quality producers are excluded, thereby inducing an inefficient outcome.

Estimation of Search Frictions in the British Electricity Market

This paper studies consumer search and pricing behaviour in the British domestic electricity market following its opening to competition in 1999. We develop a sequential search model in which an incumbent and an entrant group compete for consumers who nd it costly to obtain information on prices other than from their current supplier. We use a large data set on prices and input costs to structurally estimate the model. Our estimates indicate that consumer search costs must be relatively high in order to rationalize observed pricing patterns. We confront our stimates with observed switching behaviour and nd they match well. Keywords:electricity ; consumer search ; price competition JEL Classification: C14 ; D83 ; L13

Testing Models of Consumer Search using Data on Web Browsing and Purchasing Behavior

Using a large data set on web browsing and purchasing behavior we test to what extent consumers are searching in accordance to various classical search models. We nd that the benchmark model of sequential search with a known distributions of prices can be rejected based on the recall patterns we observe in the data. Moreover, we show that even if consumers are initially unaware of the price distribution and have to learn the price distribution, observed search behavior for given consumers over time is more consistent with non-sequential search than sequential search with learning. Our ndings suggest non-sequential search provides a more accurate description of observed consumer search behavior. We then utilize the non-sequential search model to estimate the price elasticities and markups of online book retailers.consumer search, electronic commerce, consumer behavior

On the Identification of the Costs of Simultaneous Search

This paper studies the identification of the costs of simultaneous search in a class of (portfolio) problems studied by Chade and Smith (2006). We show that aggregate data from a single market, or disaggregate data from a single market segment, do not provide sufficient information to identify the costs of simultaneous search in any reasonable interval. We then show that by pooling aggregate data from multiple markets, or disaggregate data from multiple market segments, the econometrician can identify the costs of simultaneous search in a non-empty interval. Within the context of specific examples, we illustrate that identification of the search cost distribution in its full support may easily be obtained.search costs, portfolio choice, non-parametric identification

Nonsequential Search Equilibrium with Search Cost Heterogeneity

We generalize the model of Burdett and Judd (1983) to the case where an arbitrary finite number of firms sells a homogeneous good to buyers who have heterogeneous search costs. We show that a price dispersed symmetric Nash equilibrium always exists. Numerical results show that the behavior of prices with respect to the number of firms hinges upon the shape of the search cost distribution: when search costs are relatively concentrated (dispersed), entry of firms leads to higher (lower) average prices.nonsequential search, oligopoly, arbitrary search cost distributions

Estimation of search frictions in the British electricity market

This paper studies consumer search and pricing behavior in the British domestic electricity market following its opening to competition in 1999. We develop a sequential search model in which an incumbent and an entrant group compete for consumers who find it costly to obtain information on prices other than from their current supplier. We use a large data set on prices and input costs to structurally estimate the model. Our estimates indicate that consumer search costs must be relatively high in order to rationalize observed pricing patterns. We confront our estimates with observed switching behavior and find they match well

Estimation of search frictions in the British electricity market

This paper studies consumer search and pricing behaviour in the British domestic electricity market following its opening to competition in 1999. We develop a sequential search model in which an incumbent and an entrant group compete for consumers who nd it costly to obtain information on prices other than from their current supplier. We use a large data set on prices and input costs to structurally estimate the model. Our estimates indicate that consumer search costs must be relatively high in order to rationalize observed pricing patterns. We confront our estimates with observed switching behaviour and nd they match well

Comparison sites

Web search technologies are fundamental tools for navigating the Internet. One particular type of search technology is "shopbots", or comparison sites. The emergence of Internet shopbots and their implications for price competition and market efficiency are the focus of this paper. We develop a simple model where a price comparison site tries to attract (possibly vertically and horizontally differentiated) online retailers, on the one hand, and consumers, on the other. Analysis of the model reveals that differentiation among the products of the retailers and their ability to price discriminate between on- and off-comparison-site consumers play a critical role. When products are homogeneous, if online retailers cannot charge different on- and off-the-comparison-site prices, then the comparison site has incentives to charge fees so high that some firms are excluded, which generates price dispersion and an inefficient outcome. By contrast, when on- and off-comparison-site prices can be different, the comparison site attracts all the players to the platform and the allocation is efficient. A similar result obtains when products are horizontally differentiated. In that case, the comparison site becomes an aggregator of product information and no matter whether firms can price discriminate or not, the comparison site attracts all the players to the platform and an efficient outcome ensues. We argue that the lack of vertical product differentiation may also be critical for this efficiency result. In fact, we show that when quality differences are large, the comparison site may find it profitable to charge fees that effectively exclude low quality producers, thereby inducing an inefficient outcome.shopbots; two-sided market; intermediation; price discrimination; product differentiation;