@proceedings {46, title = {Buy-it-now or Take-a-chance: A Simple Sequential Screening Mechanism}, journal = {Proceedings of the 20th international conference on World wide web}, volume = {WWW {\textquoteright}11}, number = {March 2011}, year = {2011}, pages = {147-156}, publisher = {International World Wide Web Conference Committee}, address = {Hyderabad, India}, abstract = {We present a simple auction mechanism which extends the second-price auction with reserve and is truthful in expectation. This mechanism is particularly effective in private value environments where the distribution of valuations are irregular. Bidders can {\textquotedblleft}buy-it-now{\textquotedblright}, or alternatively {\textquotedblleft}takea- chance{\textquotedblright} where the top d bidders are equally likely to win. The randomized take-a-chance allocation incentivizes high valuation bidders to buy-it-now. We show that for a large class of valuations, this mechanism achieves similar allocations and revenues as Myerson{\textquoteright}s optimal mechanism, and outperforms the second-price auction with reserve. In addition, we present an evaluation of bid data from Microsoft{\textquoteright}s AdECN platform. We find the valuations are irregular, and counterfactual experiments suggest our BINTAC mechanism would improve revenue by 11\% relative to an optimal second-price mechanism with reserve.}, url = {https://dl.acm.org/citation.cfm?id=1963429}, author = {L. Elisa Celis and Gregory Lewis and Markus Mobius and Hamid Nazerzadeh} }