1. A method of predicting interest levels associated with publication and content item combinations, the method implemented by a server computing device that is communicatively coupled to at least one client computing device, the method comprising: determining a first interest level associated with a first combination including a first publication and a first set of keywords used for selecting a first content item to be displayed in conjunction with the first publication; determining a second interest level associated with a second combination including a second publication and a second set of keywords used for selecting a second content item to be displayed in conjunction with the second publication; determining a first dependency of the first interest level on the first set of keywords and a second dependency of the first interest level on a first provider of publications associated with the first publication; determining a third dependency of the second interest level on the second set of keywords and a fourth dependency of the second interest level on a second provider of publications associated with the second publication; and generating (i) a proposed combination of the first publication and one of the first set of keywords and the second set of keywords and (ii) a predicted interest level associated with the proposed combination, based at least on the first dependency, the second dependency, the third dependency, and the fourth dependency.