Some embodiments of the invention provide techniques for placing “placeholder” bids in an auction associated with online advertising marketplace. Placeholder bids can include bids that are not actually entered or placed in the auction or marketplace. Rather, placeholder bids can include hypothetical bids. Impacts of placeholder bids, should the placeholder bids have been entered or placed as actual bids, can be assessed. An assessment can include assessing an impact on auction and marketplace parameters, an impact on bid or campaign performance, and an impact on downstream parameters such as user behavior, such as associated conversions or purchasing.