線上拍賣的誘餌危機之研究

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[email protected] [email protected]

1

(1) (2)

(3) (4)

(shill bidding crisis)[10]

Abstract

The emergence of Internet and World Wide Web offers a fast and yet convenient transaction platform for online auction. However, there are many potential risks for bidders in online auction. They are (1) information asymmetry, (2) uncertainty, (3) herding bias, and (4) uncontrollable risk. These problems induce shill bidding crisis – sellers use shill biddings to lure potential bidders to make them pay price higher than the real price of auctioned items. This study first reviews the literatures regarding to shill bidding strategies. Then, a new shill bidding strategy discovered by this study is introduced and analyzed in details. This study also assesses the effect of sellers’ reputation on shill bidding auctions. The results show that shill bidding auctions have a higher price-increment ration during the initial stage of an auction compared to normal auctions. The same tendency also happens to the number of bids. However, in shill bidding auctions and normal auctions, the reputation of sellers does not make any significance. Keywords: online auction, shill bidding, herding bias, information asymmetry

1.

eBay Yahoo! eBay

1995 Yahoo! 1995 eBay Yahoo!2004 75.4 2003 28.3 [1] : [13] 250 4 [6]: (1) (information asymmetry)

(2)

eBay Yahoo!

(feedback system) [8]

( )

(3) (herding bias syndrome)

(herding bias) [9] [7] ( 89000 ) (4) (uncontrollable risk) (feedback value) 3 [14][15] [3] [4] (1) (2) (3) : 1208

2.

5 3 4 5 : (1) ? ( ) [10] (competitive

shill bidding )[11] Kauffman Wood

[11][12] (2) (1) (1) [11][12][13] (3) (2) (2) [11] (4)

(3)

[3] ? (5) (1) (3) n n+1 ( 1 2) n n n+1 Yahoo! n 1 1 2

3.

1 Yahoo! 1 2 17 1 *n6816 13:26 2 Yahoo! *n6315 *n6816 2 1 (*n6816) 1 *nn048 3,450 3.1 ( ) : 1 H1: H2: H3: H4: H5: H6: H1 H2 H3 H1 H4 H2 H5 ( Yahoo!) [5] H6 [5] 3.2 Yahoo! / / 1208 2005/2/1 2005/3/31 9 14 1208 652 5852

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[11] Kauffman Wood 2 1208 19 ( ) 1 2 37 ( ) 2 ( 9 14 ) : 3 : 0.4139:0.0943 0.2967:0.1036, 0.2309:0.2486 ( ( )) ? ( ) ; 4 : 38:16 20:9 34:15 : 2 3 4

4.

2 (H1~H6) 4.1 0

H

1

H

Kolmogorov-Smirnov K-S Lilliefors p-value 0.2 T p-value<0.2 Mann-Whitney U

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0.2 t 0.2 Mann-Whitney U 3 3 Mann-Whitney U 4.2 3 ( ) 3 H1 H2 H3 H4 2 2 H5 H6 ( ) H5 Kaffuman Wood [11]: : H6 :

5.

: ; ( ) Yahoo! 1. : Yahoo! 2. : Yahoo! [2] 2 Yahoo! Yahoo! Yahoo! ( Yahoo!) Mann- Whitney U Wilcoxon W Z Sig 1 75 778 -4.98 .000_*** 2 115 818 -4.20 .000_*** 3 236 939 -2.06 .039_* 4 176 879 -3.07 .002_** 5 317.5 507.5 -.59 .556 6 317 1020 -.63 .53 P<0.001 *** P<0.005 ** P<0.05 *

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[1] 2004 http://www.pconline.com.cn/news/nw/0404/35065 9.html (Accessed on July 6, 2005). [2] http://pages.tw.ebay.com/help/basics/f-selling.html (Accessed on July 6, 2005). [3] http://tw.help.yahoo.com/auct/faq/asell/asell-06.ht ml (Accessed on July 6, 2005). [4] http://tw.help.yahoo.com/auct/faq/asell/asell-05.ht ml (Accessed on July 6, 2005). [5] http://tw.help.yahoo.com/auct/faq/agen/agen-07.ht ml (Accessed on July 6, 2005).

[6] S. Ba and P. A. Pavlou, “Evidence of the effect of trust building technology in electronic markets: price premiums and buyer behavior,” MIS Quarterly, Vol. 26, No. 3, pp. 243-268, 2002. [7] P. Bajari and A. Hortac_su, “Winner’s curse,

reservation prices, and endogenous entry: empirical insights from eBay auctions,” Journal of Economics, Vol. 34, No. 2, pp. 329-355, 2003. [8] C. Dellarocas, “Efficiency and Robustness of

eBay-like online feedback mechanisms in environments with moral hazard,” Working paper, 2003, http://ccs.mit.edu/dell/SITE%202002.pdf. [9] U.M. Dholakia, S. Basuroy, and K. Soltysinski,

“Auction or agent (or both)? A study of moderators of herding bias in digital auctions,” International Journal of Research in Marketing, Vol. 19 pp. 115-130, 2002.

[10] eBay, Shill bidding: what it is and why it’s not permitted on eBay,

http://pages.ebay.com/help/community/shillBiddi ng.html (Accessed on July 6, 2005).

[11] R. J. Kauffman and C. A. Wood, “Running up the bid: detecting, predicting, and preventing reserve price shilling in online auctions,” Proceedings of the 5th_{international conference on Electronic}

commerce, pp. 259-265, 2003.

[12] R. J. Kauffman and C. A. Wood, “The effects of shilling on final bid prices in online auction,” Electronic Commerce Research and Applications, pp. 18-31, 2005.

[13] R. P. McAfee and J. McMillan, “Auctions and bidding,” Journal of Economic Literature, Vol. 1, No. 25, pp. 699-738, 1987.

[14] W. Wang, Z. Hidvégi, and B. Whinston, “Shill bidding in English auctions,” Working paper, Center for research on E-Commerce, McComb School of Business, U. Texas, Austin, 2001.

Proceedings of the 35th Annual Hawaii International Conference on System Sciences (HICSS'02), Hawaii, 2002.