Probabilistic Patents

We model a homogeneous product environment where identical e-retailers endogenously engage in both brand advertising (to create loyal customers) and price advertising (to attract 'shoppers'). Our analysis allows for 'cross-channel' effects; indeed, we show that price advertising is a substitute for brand advertising. In contrast to models where loyalty is exogenous, these crosschannel effects lead to a continuum of symmetric equilibria; however, the set of equilibria converges to a unique equilibrium as the number of potential e-retailers grows arbitrarily large. Price dispersion is a key feature of all of these equilibria, including the limit equilibrium. While each firm finds it optimal to advertise its brand in an attempt to 'grow' its base of loyal customers, in equilibrium, branding (1) reduces firm profits, (2) increases prices paid by loyals and shoppers, and (3) adversely affects gatekeepers operating price comparison sites. Branding also tightens the range of prices and reduces the value of the price information provided by a comparison site. Using data from a price comparison site, we test several predictions of the model.Price dispersion

Brand and Price Advertising in Online Markets

We model a homogeneous product environment where identical e-retailers endogenously engage in both brand advertising (to create loyal customers) and price advertising (to attract "shoppers"). Our analysis allows for "cross-channel" effects; indeed, we show that price advertising is a substitute for brand advertising. In contrast to models where loyalty is exogenous, these cross-channel effects lead to a continuum of symmetric equilibria; however, the set of equilibria converges to a unique equilibrium as the number of potential e-retailers grows arbitrarily large. Price dispersion is a key feature of all of these equilibria, including the limit equilibrium. While each firm finds it optimal to advertise its brand in an attempt to "grow" its base of loyal customers, in equilibrium, branding (1) reduces firm profits, (2) increases prices paid by loyals and shoppers, and (3) adversely affects gatekeepers operating price comparison sites. Branding also tightens the range of prices and reduces the value of the price information provided by a comparison site. Using data from a price comparison site, we test several predictions of the model.Price dispersion

Are Prices ‘Sticky’ Online? Market Structure Effects and Asymmetric Responses to Cost Shocks in Online Mortgage Markets

We analyze daily mortgage rates posted by online lenders at the price comparison site, Microsurf. While cost shocks occurred almost daily in our sample, quoted mortgage rates are surprisingly rigid: Only 16 percent of the posted rates represent changes. However, firms that adjusted rates in response to cost shocks did so quite rapidly; about 98 percent of a cost shock was passed through within two days of the cost shock. Duration analysis reveals that the observed rigidity in rates systematically depends on market structure: Online mortgage rates are 30 to 40 percent more durable in concentrated markets than in markets where there are many competitors. We also find that rates posted online tend to exhibit downward stickiness; rate adjustments in response to cost increases are about twice the corresponding adjustments for cost decreases.mortgage rate, price adjustment, price rigidity, price dispersion

Price Dispersion in the Lab and on the Internet: Theory and Evidence

Price dispersion is ubiquitous in settings that closely approximate textbook Bertrand competition. We show (Propositions 2 and 3) that only a little bounded rationality among sellers is needed to rationalize such dispersion. A variety of statistical tests, based on data sets from two independent laboratory experiments and structural estimates of the parameters of our models, suggest that bounded rationality based theories of price dispersion organize the data remarkably well. Evidence is also presented which suggests that the models are consistent with data from a leading Internet price comparison site.Price dispersion

Red Queen Pricing Effects in E-Retail Markets

A standard “solution” offered to the deleterious effects of all-out price competition is for firms to engage in differentiation strategies. This solution, however, depends critically on the inability of rivals to imitate a successful differentiation strategy. With imitation, we show how “Red Queen” pricing effects can arise: All firms have an incentive to vertically differentiate and increase markups, yet imitation by rivals drives prices down toward pre-differentiation levels. Thus, the price premia arising from differentiation strategies in eretailing critically depend on the number of other firms that imitate the strategies. Based on data from Shopper.com, we find that an online firm that unilaterally differentiates itself from its rivals by participating in CNet’s Certified Merchant program enjoys a 5 to 17 percent price premium. However, when other firms also follow this strategy, the price premium vanishes.Pricing, Product Differentiation, Red Queen Effect, Internet, Reputation

Is Antitrust Too Complicated for Generalist Judges? The Impact of Economic Complexity and Judicial Training on Appeals

Modern antitrust litigation sometimes involves complex expert economic and econometric analysis. While this boom in the demand for economic analysis and expert testimony has clearly improved the welfare of economists—and schools offering basic economic training to judges—little is known about the empirical effects of economic complexity or judges' economic training on decision-making in antitrust litigation. We use a unique data set on antitrust litigation in district courts during 1996—2006 to examine whether economic complexity impacts decisions in antitrust cases, and thereby provide a novel test of the frequently asserted hypothesis that antitrust analysis has become too complex for generalist judges. We also examine the impact of one institutional response to economic complexity - basic economic training by judges. We find that decisions involving the evaluation of complex economic evidence are significantly more likely to be appealed, and decisions of judges trained in basic economics are significantly less likely to be appealed than are decisions by their untrained counterparts. Our results are robust to a variety of controls, including the type of case, circuit, and the political party of the judge. Our tentative conclusion, based on a revealed preference argument that views a party’s appeal decision as an indication that the district court got the economics wrong, is that there is support for the hypothesis that some antitrust cases are too complicated for generalist judges.antitrust, Daubert, complexity, economic training, expert witness

Price Dispersion in the Small and in the Large: Evidence from an Internet Price Comparison Site

This paper examines 4 million daily price observations for over 1000 consumer electronics products on the price comparison site Shopper.com. We find little support for the notion that prices on the Internet are converging to the “law of one price.” In addition, observed levels of price dispersion vary systematically with the number of firms listing prices. The difference between the two lowest prices (the “gap”) averages 22 percent when two firms list prices, and falls to 3.5 percent in markets where 17 firms list prices. These empirical results are an implication of a general “clearinghouse” model of equilibrium price dispersion.Bertrand Competition, Internet, Law of One Price, Price dispersion

Temporal Price Dispersion: Evidence from an Online Consumer Electronics Market

Economic theory indicates that E-retailers competing at price comparison sites, such as Shopper.com, must charge prices that cannot be systematically predicted by their rivals. Consistent with theory, we find significant variation in the identity of the lowprice firm as well as the level of the lowest price for 36 of the best-selling consumer electronics products sold at Shopper.com between November 1999 and May 2001. The observed pricing patterns can be explained by firms engaging in short-term price promotions in an attempt to avoid the deleterious outcome associated with price competition. Based on our arguments and the evidence presented, the managerial implications are clear: Strategic unpredictability in prices—through the use of hit and run sales—is a widely used and effective weapon for avoiding all-out price competition in online markets.Temporal price dispersion, price comparison sites, e-retail, sales promotion

Information, Search, and Price Dispersion

We provide a unified treatment of alternative models of information acquisition/transmission that have been advanced to rationalize price dispersion in online and offline markets for homogeneous products. These different frameworks -- which include sequential search, fixed sample search, and clearinghouse models -- reveal that reductions in (or the elimination of) consumer search costs need not reduce (or eliminate) price dispersion. Our treatment highlights a "duality" between search-theoretic and clearinghouse models of dispersion, and shows how auction-theoretic tools may be used to simplify (and even generalize) existing theoretical results. We conclude with an overview of the burgeoning empirical literature. The empirical evidence suggests that price dispersion in both online and offline markets is sizeable, pervasive, and persistent and does not purely stem from subtle differences in firms' products or services.

Persistent Price Dispersion in Online Markets

Using data from one of the Internet’s leading price comparison sites for consumer electronics products, we present evidence for the persistence of price dispersion for 36 homogeneous products. The markets for these products are “thick” with an average of over 20 firms selling each product. We show that prices do not converge to the “law of one price” even after an 18 month period. This finding is robust to controls for differences in shipping charges and inventories. Further, we show that product life cycle effects lead to changes in the number of competing firms and the range of price dispersion consistent with the theoretical predictions of the Varian (1980) model. The average number of competing firms declines from about 28 to 10 during the final five months of our dataset. Over this same period, the average range in prices decreases from about 75 percent to 30 percent. After accounting for firm heterogeneities in costs, branding, reputation, trust, product availability and shipping costs, 28 percent of the variation in prices charged for homogeneous products remains unexplained. This is also consistent with the Varian model.Price dispersion, Internet, Law of One Price