15. A method as recited in claim 1 , further comprising generating the first set of items and the second set of items by: for each item in the first and second set of items: identifying an item that is associated with a first spelling of the term in a first search query and a re-formulation of the term in a second search query; associating the item with the first spelling in the first set; associating the item with the re-formulation of the term in the second set; and assigning a stronger association between the item and the re-formulation of the term than the association between the item and the first spelling of the term.
1. A computer-implemented method comprising steps of: receiving a search query that includes a first spelling of a term; generating a second spelling of the term; accessing a first set of items that are associated with the first spelling of the term; accessing a second set of items that are associated with the second spelling of the term; performing a comparison between the first set to the second set at least in part by determining a degree to which items in the first set overlap with items in the second set; determining how to respond to the search query based, at least in part, on the comparison; determining a relative ranking of the items in the first set of items, indicating how strongly a particular item in the first set is associated with a user-provided spelling of the term as compared to the remainder of the items in the first set; determining a relative ranking of the items in the second set of items, indicating how strongly a particular item in the second set is associated with an alternative spelling of the term as compared to the remainder of the items in the second set; identifying a plurality of overlap items that are included in both the first set of items and the second set of items; increasing a degree to which the items in the first set correlate to items in the second set based on a determination that a first item in the plurality of overlap items has a relative ranking above a first threshold; and decreasing the degree to which the items in the first set correlate to items in the second set based on a determination that a second item in the plurality of overlap items has a relative ranking below a second threshold; wherein the steps are performed by one or more computing devices.