5. The computer-implemented method of claim 1 , wherein each intervening event serves to reduce an amount of weight given to the item selection event for purposes of calculating the relationship value.
1. A computer-implemented method of determining a degree of association between a search string and an item, the computer-implemented method comprising: as implemented by one or more computing devices configured with specific executable instructions, retrieving a user event history sequence that identifies a number of user actions that occurred during user interaction with an electronic repository, wherein the user event history sequence comprises a search event in which the user submitted a request to search items in the electronic repository; identifying a search string submitted by the user in association with the search event; identifying a subsequent item selection event in the user event history sequence, wherein the subsequent item selection event corresponds to a selection by the user of an item in the electronic repository, said subsequent item selection event occurring after the search event; determining a number of intervening events in the user event history sequence that each occur after the search event and before the subsequent item selection event; and calculating a relationship value representing a probability that a user who submits the search string will subsequently select the item, wherein the relationship value is calculated based at least in part on the determined number of intervening events that occur after the search event and before the subsequent item selection event in the user event history sequence.