TY - JOUR AU - Cary,Matthew AU - Das,Aparna AU - Edelman,Benjamin AU - Giotis,Ioannis AU - Heimerl,Kurtis AU - Karlin,Anna R. AU - Mathieu,Claire AU - Schwarz,Michael TI - On Best-Response Bidding in GSP Auctions JF - National Bureau of Economic Research Working Paper Series VL - No. 13788 PY - 2008 Y2 - February 2008 UR - http://www.nber.org/papers/w13788 L1 - http://www.nber.org/papers/w13788.pdf N1 - Author contact info: Matthew Cary University of Washington Seattle, WA 98195 E-Mail: cary@cs.washington.edu Aparna Das Brown University Computer Science Department Box 1910 Providence, RI 02912 E-Mail: aparna@cs.brown.edu Benjamin Edelman Harvard Business School Baker Library 445 Soldiers Field Boston, Massachusetts 02163 E-Mail: bedelman@hbs.edu Ioannis Giotis University of Washington Department of Computer Science and Engineering Seattle, WA 98195 E-Mail: giotis@cs.washington.edu Kurtis Heimerl University of Washington Department of Computer Science and Engineering Seattle, WA 98195 E-Mail: heimerl@cs.washington.edu Anna R. Karlin University of Washington Department of Computer Science and Engineering Box 352350 Seattle, WA 98195 E-Mail: karlin@cs.washington.edu Claire Mathieu Brown University Computer Science Department Box 1910 Providence, RI 02912 E-Mail: claire@cs.brown.edu Michael Schwarz Yahoo! Research 2397 Shattuck Ave Berkeley, CA 94704 Fax: 510/704-2401 E-Mail: mschwarz@yahoo-inc.com AB - How should players bid in keyword auctions such as those used by Google, Yahoo! and MSN? We model ad auctions as a dynamic game of incomplete information, so we can study the convergence and robustness properties of various strategies. In particular, we consider best-response bidding strategies for a repeated auction on a single keyword, where in each round, each player chooses some optimal bid for the next round, assuming that the other players merely repeat their previous bids. We focus on a strategy we call Balanced Bidding (bb). If all players use the bb strategy, we show that bids converge to a bid vector that obtains in a complete information static model proposed by Edelman, Ostrovsky and Schwarz (2007). We prove that convergence occurs with probability 1, and we compute the expected time until convergence. ER -