A shadow ad can be evaluated by receiving an ad request, identifying at least one shadow ad and at least one actual ad based on the received ad request, generating an ad ranking by analyzing one or more criteria associated with the identified at least one shadow ad and the at least one actual ad, and selecting one or more of the identified at least one shadow ad and the at least one actual ad based on the ad ranking. Further, the at least one shadow ad can be associated with one or more campaign parameters corresponding to a shadow ad campaign. Additionally, the ad request can be received from an online advertising system.