1. A system comprising: one or more computers configured to perform operations comprising: receiving a query and a location identifier identifying a geographic location; obtaining a location-specific set of search results responsive to the query and a global set of search results responsive to the query, wherein the location-specific set of search results is specific to the associated geographic location for the query and the global set of search results is not specific to the associated geographic location for the query; determining one or more scores measuring at least one of quality or responsiveness for the location-specific set of search results; determining one or more scores including a clustering score for the global set of search results, wherein the clustering score is a measure of the geographical clustering of entities associated with the global set of search results relative to each other or around a single location unrelated to the associated geographic location of the query; selecting either the global set of search results or the location-specific set of search results as a primary set of search results based on the one or more scores for the location-specific and the one or more scores for the global set of search results; and identifying one or more identified search results in the primary set of search results for presentation in response to the query.