[강병남교수] NewScientist.com news
Mathematicians snipe to win on eBay 2006.6.23
The best way to win an online auction is to wait until the very last moment before making a bid in the hope no one else will have time to respond.
This strategy is already practised by many auction aficionados and is known as "sniping". Now a mathematical analysis by researchers from Seoul National University in Korea has confirmed that it gives the best chance of winning.
Byungnam Kahng and his colleague Inchang Yang analysed more than half a million auctions on the US and Korean versions of the auction site eBay in an effort to determine the best strategy for bidding. They saw a mathematical pattern in the bidding behaviour of bidders and derived a simple power-law equation to describe this.
Best probability
This power law reflects the fact that bids become more frequent as the end of an auction approaches. The researchers used this equation to determine the best time to make a winning bid.
They conclude that sniping is the best approach. "Bidding at the last moment is a rational and effective strategy to win in an eBay auction," the researchers write in the July edition of the journal Physical Review E.
The research builds on a 2002 paper in the American Economic Review by economists Al Roth from Harvard University in the US and Axel Ockenfels from the University of Cologne in Germany.
Time interval
"We noted that the way bids are distributed over the duration of an internet auction obeys what is known as a power law," Roth told New Scientist. This law remains describes the distribution of bids regardless of the time interval examined, Roth says.
Many eBay pundits already claim that sniping is the most efficient strategy: it gives others little time to respond with a higher bid and also lulls early bidders into a false sense of security about how much interest there is. The strategy only applies online, however. Real-life auctioneers always offer all bidders a final chance to make an offer.
Even in online auctions, Roth points out that sniping takes extra effort, and may not always be worth it. "If you're sitting at your computer and have time to be a sniper, then do that," he says. "But if you have to be at work, or the auction ends after your bedtime, just put in a sensible bid and sleep the sleep of the just."
Journal references: Physical Review E (vol 73, p 067101), American Economic Review (vol 92, p 1093)
The best way to win an online auction is to wait until the very last moment before making a bid in the hope no one else will have time to respond.
This strategy is already practised by many auction aficionados and is known as "sniping". Now a mathematical analysis by researchers from Seoul National University in Korea has confirmed that it gives the best chance of winning.
Byungnam Kahng and his colleague Inchang Yang analysed more than half a million auctions on the US and Korean versions of the auction site eBay in an effort to determine the best strategy for bidding. They saw a mathematical pattern in the bidding behaviour of bidders and derived a simple power-law equation to describe this.
Best probability
This power law reflects the fact that bids become more frequent as the end of an auction approaches. The researchers used this equation to determine the best time to make a winning bid.
They conclude that sniping is the best approach. "Bidding at the last moment is a rational and effective strategy to win in an eBay auction," the researchers write in the July edition of the journal Physical Review E.
The research builds on a 2002 paper in the American Economic Review by economists Al Roth from Harvard University in the US and Axel Ockenfels from the University of Cologne in Germany.
Time interval
"We noted that the way bids are distributed over the duration of an internet auction obeys what is known as a power law," Roth told New Scientist. This law remains describes the distribution of bids regardless of the time interval examined, Roth says.
Many eBay pundits already claim that sniping is the most efficient strategy: it gives others little time to respond with a higher bid and also lulls early bidders into a false sense of security about how much interest there is. The strategy only applies online, however. Real-life auctioneers always offer all bidders a final chance to make an offer.
Even in online auctions, Roth points out that sniping takes extra effort, and may not always be worth it. "If you're sitting at your computer and have time to be a sniper, then do that," he says. "But if you have to be at work, or the auction ends after your bedtime, just put in a sensible bid and sleep the sleep of the just."
Journal references: Physical Review E (vol 73, p 067101), American Economic Review (vol 92, p 1093)