1. A computer-implemented method for searching a content collection, comprising: under control of one or more computer systems configured with executable instructions, receiving a search request and responsively selecting a candidate subset of the content collection based at least in part on the search request; identifying a recent content event history associated with at least one content piece of the candidate subset; determining a set of ranking components including an observed ranking component based on the recent content event history; determining a set of ranking scores for content in the candidate subset of the content collection based at least in part on the set of ranking components; applying an inverted decay transformation to the observed ranking component to yield a transformed ranking component, wherein applying the inverted decay transformation corresponds to simulating an extended behavioral data history of the at least one content piece; adjusting at least one of the ranking scores of the set of ranking scores based on the transformed ranking component to yield an adjusted ranking score; and providing for presentation at least a reference to content in a ranked subset of the candidate subset of the content collection, the ranked subset ordered based at least in part on the set of ranking scores that includes the adjusted ranking score.