13. The non-transitory computer readable storage medium of claim 9 , wherein determining, from the data describing the resources, a search hypothesis score comprises determining a quality metric value for search results provided in response to the hypothesis search query.
14. The non-transitory computer readable storage medium of claim 13 , wherein determining the quality metric value comprises determining a quality score that is a measure of quality of resources identified by the search results, the measure of quality being independent of user interactions at user devices.