24. The computer storage medium of claim 23 , wherein determining the respective combined score for each pattern used to generate the candidate additional fact comprises: determining a frequency score for the pattern from a total number of extractions generated by applying the pattern; determining a coherence score for the pattern that measures how semantically related the attributes for which the pattern generates facts are; and determining the combined score for the pattern by combining the frequency score and the coherence score.
24. The computer storage medium of claim 23 , wherein determining the respective combined score for each pattern used to generate the candidate additional fact comprises: determining a frequency score for the pattern from a total number of extractions generated by applying the pattern; determining a coherence score for the pattern that measures how semantically related the attributes for which the pattern generates facts are; and determining the combined score for the pattern by combining the frequency score and the coherence score. 25. The computer storage medium of claim 24 , where determining the coherence score for the pattern comprises: determining a respective high-dimensional vector representation of each attribute for which the pattern generates facts; determining, for each possible pair of attributes selected from the attributes for which the pattern generates facts, a respective pairwise coherence score from the high-dimensional vector representations of the attributes in the pair; and determining the coherence score for the pattern from the pairwise coherence scores.