The authors develop a general parametric modeling framework for bidding behavior in Internet auctions. Toward this end, they incorporate four key components of the bidding process under their framework: whether people bid on an auction, (if so) who bids, when they bid, and how much they bid over the entire sequence of bids in an auction. This integrated framework is based on a single, latent, time-varying construct of consumer willingness to bid, which bidders have and update for a particular auction item over the course of the auction duration