A search facility may optimize search result ranking by applying inverted decay transformations to history-dependent ranking components. Ranking scores for content in a content collection may be based on a set of ranking components including history-dependent ranking components. History-dependent ranking components may be based on historical behavioral data such as historical searches, actions taken with respect to content such as viewing content and content-related purchases. Content recently added to the content collection may be disadvantaged relative to content with an established history. Inverted decay transformations may correspond to simulations of additional historical behavioral data.