Fortunately for economists, eBay offers solutions as well as problems. With hundreds of thousands of auctions starting every day, the auction site provides masses of data. And if the publicly available data isn't enough, it's also easy to conduct an experiment "in the field", studying bidders in their natural habitat.
亚利桑那大学(University of Arizona)经济学家戴维·赖利(David Reiley)自eBay出现之前就一直在研究网上拍卖。在最近与拉玛·卡特卡尔(Rama Katkar)合著的一篇论文中，他对eBay拍卖中的保留价格应该公开还是保密的问题进行了研究。
David Reiley, an economist at the University of Arizona, has been studying online auctions since before eBay existed. In a recent paper with Rama Katkar, he investigated whether reserve prices in eBay auctions should be open or secret.
Auction theory offers an argument that a secret reserve price is better. A secret reserve price allows bidders to see each others' gradually ascending bids and thus draw confidence that they are not alone in prizing the item. Even though the bids are too low to beat the reserve, they serve an important purpose of reassuring bidders that others are also interested. An open reserve price on eBay makes that reassurance impossible; nobody can submit a bid below the open reserve, and lacking any signs of confidence from other bidders, there is a danger that nobody may submit a bid above it either.
There are too many imponderables to tell whether this theoretical argument is what really counts in practice. So Katkar and Reiley put the theory to the test by simply selling 50 matched pairs of collectible cards, half with an open reserve price and half with a secret reserve price of the same level. Their conclusion, contrary to the theoretic argument, is that secret reserve prices are counterproductive. Far from stimulating interest they seem to put off bidders,who perhaps fear that a secret reserve is secret because it is far too high. Not wishing to waste their time, many of them just click "back" on their browsers and find somewhere else to bid.
The conclusion may not shake the world but the method is important. David Reiley was one of the first economists to realise that the internet was generating vast amounts of researchable data. Now that data, from sites ranging from eBay and Amazon to Match.com, is enriching the study of economics. It may enrich a few eBay sellers, too.
蒂姆·哈福德的著作《卧底经济学家》(The Undercover Economist)(小布郎出版社(Little, Brown))目前已经出版平装本。
Tim Harford's book "The Undercover Economist" (Little, Brown) is out now in paperback.