Neel Sundaresan

eBay Research Labs
2065 Hamilton Avenue
San Jose, CA 95125

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NBER Working Papers and Publications

August 2014Consumer Price Search and Platform Design in Internet Commerce
with Michael Dinerstein, Liran Einav, Jonathan Levin: w20415
Search frictions can explain why the "law of one price" fails in retail markets and why even firms selling commodity products have pricing power. In online commerce, physical search costs are low, yet price dispersion is common. We use browsing data from eBay to estimate a model of consumer search and price competition when retailers offer homogeneous goods. We find that retail margins are on the order of 10%, and use the model to analyze the design of search rankings. Our model explains most of the effects of a major re-design of eBay's product search, and allows us to identify conditions where narrowing consumer choice sets can be pro-competitive. Finally, we examine a subsequent A/B experiment run by eBay that illustrates the greater difficulties in designing search algorithms for diffe...
May 2013Sales Mechanisms in Online Markets: What Happened to Internet Auctions?
with Liran Einav, Chiara Farronato, Jonathan D. Levin: w19021
Consumer auctions were very popular in the early days of internet commerce, but today online sellers mostly use posted prices. Data from eBay shows that compositional shifts in the items being sold, or the sellers offering these items, cannot account for this evolution. Instead, the returns to sellers using auctions have diminished. We develop a model to distinguish two hypotheses: a shift in buyer demand away from auctions, and general narrowing of seller margins that favors posted prices. Our estimates suggest that the former is more important. We also provide evidence on where auctions still are used, and on why some sellers may continue to use both auctions and posted prices.
April 2012Sales Taxes and Internet Commerce
with Liran Einav, Dan Knoepfle, Jonathan D. Levin: w18018
We estimate the sensitivity of Internet retail purchasing to sales taxes using data from the eBay marketplace. Our first approach exploits the fact that seller locations are revealed only after buyers have expressed interest in an item by clicking on its listing. We use millions of location "surprises" to estimate price elasticities with respect to the effective sales tax. We then use aggregated data to estimate cross-state substitution parameters, and substitution between offline and online purchases, relying on the variation in state and local sales taxes, and on changes in these rates over time. We find substantial sensitivity to sales taxes. Using our item-level approach, we find a price elasticity of around -2 for interested buyers. Using our aggregate approach, we find that a one per...

Published: Liran Einav & Dan Knoepfle & Jonathan Levin & Neel Sundaresan, 2014. "Sales Taxes and Internet Commerce," American Economic Review, American Economic Association, vol. 104(1), pages 1-26, January. citation courtesy of

September 2011Learning from Seller Experiments in Online Markets
with Liran Einav, Theresa Kuchler, Jonathan D. Levin: w17385
The internet has dramatically reduced the cost of varying prices, displays and information provided to consumers, facilitating both active and passive experimentation. We document the prevalence of targeted pricing and auction design variation on eBay, and identify hundreds of thousands of experiments conducted by sellers across a wide array of retail products. We show how this type of data can be used to address questions about consumer behavior and market outcomes, and provide illustrative results on price dispersion, the frequency of over-bidding, the choice of reserve prices, "buy now" options and other auction design parameters, and on consumer sensitivity to shipping fees. We argue that leveraging the experiments of market participants takes advantage of the scale and heterogeneity o...
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