The effects of proxy bidding and minimum bid increments within eBay auctions
The effects of proxy bidding and minimum bid increments within eBay auctions
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DOI：
10.1145/1255438.1255441
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发表时间：
2007-08
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影响因子：
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通讯作者：
A. Rogers;Esther David;N. Jennings;J. Schiff
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作者：
A. Rogers;Esther David;N. Jennings;J. Schiff
我们提出了一个数学模型的eBay拍卖协议，并进行了详细的分析，eBay代理投标系统和最小出价增量的拍卖性能的影响。我们首先考虑拍卖的收入，我们分析表明，当两个独立的私人估价的投标人使用eBay代理投标系统存在一个最佳值的最小出价增量，拍卖人的收入最大化。然后，我们考虑顺序的方式，出价放置在拍卖中，我们分析表明，独立的假设有关投标人的估值分布或投标策略的数量放置的可见出价是相关的对数的潜在投标人的数量。因此，在许多情况下，只有少数潜在出价人能够提交出价并在拍卖出价历史记录中可见（尽管其他隐藏的出价人仍然有效地竞争该项目）。此外，我们通过模拟表明，最低出价增量也引入了低效率的拍卖，即投标人谁进入拍卖晚可能会发现，其估值是不足以让他们提前当前出价的最低出价增量，尽管他们实际上有最高的估价为该项目。最后，我们使用这些结果来考虑适当的策略，投标人在真实的世界eBay拍卖。我们表明，虽然最后一分钟的投标（狙击）是一个有效的策略，对投标人参与增量投标（和对那些共同的价值观），在一般情况下，延迟投标是不利的，即使延迟投标肯定会收到拍卖结束前。因此，当几个投标人提交最后一分钟的出价，我们表明，而不是寻求尽可能晚地出价，投标人应该试图成为第一个狙击手出价（即，它应该“在狙击手之前狙击”）。
We present a mathematical model of the eBay auction protocol and perform a detailed analysis of the effects that the eBay proxy bidding system and the minimum bid increment have on the auction properties. We first consider the revenue of the auction, and we show analytically that when two bidders with independent private valuations use the eBay proxy bidding system there exists an optimal value for the minimum bid increment at which the auctioneer's revenue is maximized. We then consider the sequential way in which bids are placed within the auction, and we show analytically that independent of assumptions regarding the bidders' valuation distribution or bidding strategy the number of visible bids placed is related to the logarithm of the number of potential bidders. Thus, in many cases, it is only a minority of the potential bidders that are able to submit bids and are visible in the auction bid history (despite the fact that the other hidden bidders are still effectively competing for the item). Furthermore, we show through simulation that the minimum bid increment also introduces an inefficiency to the auction, whereby a bidder who enters the auction late may find that its valuation is insufficient to allow them to advance the current bid by the minimum bid increment despite them actually having the highest valuation for the item. Finally, we use these results to consider appropriate strategies for bidders within real world eBay auctions. We show that while last-minute bidding (sniping) is an effective strategy against bidders engaging in incremental bidding (and against those with common values), in general, delaying bidding is disadvantageous even if delayed bids are sure to be received before the auction closes. Thus, when several bidders submit last-minute bids, we show that rather than seeking to bid as late as possible, a bidder should try to be the first sniper to bid (i.e., it should “snipe before the snipers”).