Talk:Vickrey auction

message: I don't think it has much to do with EBay auctions at all, I don't see that it is "similar strategically" to English auctions, and I can't see that shill bids give any advantage at all, since it is a sealed auction! (I suspect that bullet point was added by someone who though vickrey auction = EBay)
213.184.192.82 12:03, 30 March 2007 (UTC)
replies: text: Actually, EBay is an approximation of a Vickrey auction if you use the strategy of bid sniping.  If all bidders are using snipe bids (and it is their optimal strategy to do so), then the winner will pay the true valuation of the participant with the second highest valuation, plus a small epsilon based on the minimal bid increment.  The reason this occurs is that because auctions will end at a certain time, it's a player's best strategy to bid a small increment at the last possible moment.  Now, this is also assuming a one-shot auction, so the fact that there can be simultaneous auctions of perfectly substitutable items makes the one-shot Vickrey less applicable.  Other auction sites, such as amazon.com, use rules that extend the auction a certain amount of time after the last bid.  Such auctions are not equivalent to a Vickrey auction.  I first found out about this idea in Mike Wellman's tutorial at the AAAI conference last summer (2006).  The abstract can be found at . Halcyonhazard 20:33, 1 April 2007 (UTC)
thread_title:  Factual Errors 

message: Isn't eBay's auction model based on a variation of this concept? Whereas the winner pays an amount derived from the second highest bidder? -- Des Courtney 21:41, 8 Mar 2005 (UTC)
replies: text: I don't know;  I haven't used Ebay.  I'll go look at the rules on their site and tell you for sure.  The distinction is simple, though:  if the winning bidder pays what he bid, it's a first-price auction.  If the winning bidder pays the second-highest bid, it's a second-price (or Vickrey) auction. Isomorphic 21:45, 8 Mar 2005 (UTC)
replies: text: OK, not quite as simple as I thought.  Ebay seems to be running what's called a proxy auction, in which you give an upper limit and the bids are placed automatically.  However, Ebay auctions run over a period of time, and you can adjust your bid if you discover that someone has bid over your limit.   In a true Vickrey auction, the bids are all collected at once with no opportunity to revise them after learning what others are bidding.  These two are strategically equivalent if you use very simple auction models, but there can be differences once you add in psychological factors and the possibility that bidders adjust what they think the good is worth after seeing other peoples' bids. I hope that answers your question.  Isomorphic 21:58, 8 Mar 2005 (UTC)
thread_title:  Ebay? 

message: Ebay is listed as an example of a high profile users (though similar, not identical). The Wikipedia entry on AdSense states The source of all AdSense income is the AdWords program which in turn has a complex pricing model based on a Vickrey second price auction. Based on? Adding it as an example, possibly expanding on what the differences are and their impacts would seem useful to me. Any reason this is not done? 85.164.107.7 18:14, 2 Jun 2005 (UTC)
thread_title:  Examples of use 

message: The article spells it "Vickrey", but most of the web sources and also an article I have from the Phi Beta Kappa Forum Volume 85, No. 3, P. 4, spells it "Vickery". 
Are we certain that the article has it spelled correctly? If not, how do we fix it so that people will find the article and others dependent upon it? (There is a seperate article on William 'Vickrey' that would also have to be fixed if the name is misspelled.) Bill Jefferys 03:27, 4 December 2005 (UTC)
replies: text: Yes, it's spelled Vickrey.  I don't know what web sources you're using, but I suggest you compare this google search with this one. Isomorphic 03:40, 4 December 2005 (UTC)

text: I see about 35,000 hits with the right spelling, and about 390 with the wrong spelling. Isomorphic 03:07, 5 December 2005 (UTC)
thread_title:  Name misspelled? 

message: Should the reference to Milgrom's book be more fleshed out?  perhaps a link to it on Amazon or the publisher's website?  Or the ISBN?129.89.32.111 (talk) 19:22, 20 March 2008 (UTC)
thread_title:  Reference List 

message: The article seems to suggest a definition "ex post efficient (the winner is the bidder with the highest valuation)". what does the ex post efficiency exactly mean? 72.0.216.52 (talk) 00:49, 20 June 2010 (UTC)
thread_title:  Ex-post efficiency 

message: The article includes a proof that bidding the true value is optimal.  However, it does not discuss empirical validation.  Do studies show that Vickrey auctions yield higher selling prices than traditional auctions? Wadler (talk) 09:09, 24 August 2010 (UTC)
replies: text: Actually, the proof has nothing to do with the optimality of the seller's revenue, especially when compared to other auctions.  The proof states that if you are participating in a single-shot Vickrey auction with no externalities, then your optimal strategy is to bid truthfully.  In fact, when the primary desideratum is seller's optimal revenue, then Vickrey isn't usually a good choice, especially when price discovery is required because a common public price is not known.  Typically, English auctions are good for this.  The cited book on the page edited by Cramton, Shoham, and Steinberg has some good chapters on this information.  Halcyonhazard (talk) 07:00, 26 August 2010 (UTC)
thread_title:  Empirical validation 

message: Please don't write this:
: $(6-5)
: 
if you mean this:
: $(6 − 5)
: 
A minus sign is not a stubby little hyphen, and proper spacing should be used.  See WP:MOSMATH.
: 
Also, notice this difference:
: 
\begin{align}
& \max_{1 \le i \le n} x_i \\
& \mbox{max}_{1 \le i \le n} x_i
\end{align}
: 
The first is standard and correct.  The second is what I found in this article.  Wikipedians seem to use \mbox promiscuously in place of various other things that are proper usage.  There just isn't any proper way to use \mbox within Wikipedia, because Wikipedia's stripped-down version of TeX never has line-breaks, and the proper use of \mbox is to prevent line-breaks.  In some contexts \mbox and \text produce quite different results, and I find lots of people here using \mbox instead of \text (in particular \mbox in subscripts and superscripts gives much larger letters than \text does in those contexts). Michael Hardy (talk) 01:09, 12 October 2010 (UTC)
thread_title:  Math notation style 

message: Dr. Said has reviewed this Wikipedia page, and provided us with the following comments to improve its quality:
We hope Wikipedians on this talk page can take advantage of these comments and improve the quality of the article accordingly.
Dr. Said has published scholarly research which seems to be relevant to this Wikipedia article:
*Reference : Said, Maher, 2008. "Information Revelation and Random Entry in Sequential Ascending Auctions," MPRA Paper 7160, University Library of Munich, Germany.
ExpertIdeasBot (talk) 13:26, 7 June 2016 (UTC)
thread_title:  Dr. Said's comment on this article 

message: The Ethereum Name Service (ENS) used a Vickrey auction.  As of Aug 2017, the ENS controls assets on the order of  in assets locked up to hold the web domain names.  (167k+ ETH with ETH currently trading for $280+ per ETH).  Seems a rather notable use of this sort of auction mechanism.  The Future of ENS Incentives, and CodeTract ENS live tracker.  What is the Ethereum Name Service? seems a main stream press coverage article.  Google shows a number of others.  N2e (talk) 04:47, 20 August 2017 (UTC)
thread_title:  Ethereum Name Service used a Vickrey auction 

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thread_title:  External links modified 

message: Most of the weaknesses listed for both Vickrey auctions and the VCG mechanism in general are factually untrue and largely unsourced.  Shilling cannot increase seller profits, nor are there any collusion strategies that benefit buyers.  For sellers, shill bids are non-optimal strategy for the same reason that overbidding is a non-optimal strategy for buyers -- the shill bid might win.  So far as collusion is concerned, a set of colluding buyers would always do better to only submit a single bid, rather than any other combination of bids.  Even the supposed examples of zero price paid by winners are flawed, in that the VCG mechanism is easily modified to take seller costs into account and these function as a reserve price (though this tends to cause budget imbalance in the payments.)
I'd suggest removing all of the listed weaknesses, except for those that can be properly sourced. Wclark (talk) 16:59, 24 May 2023 (UTC)
thread_title:  Weaknesses