Key points are not available for this paper at this time.
This study compares Google News to LexisNexis for finding stories in the New York Times, eight large-circulation U.S. newspapers, and all English-language news outlets in each database. Inter-database agreement between Google News and LexisNexis ranged from 29% to 83%, with much of the discrepancy due to wire service exclusions: LexisNexis missed half or more of stories appearing in major papers and in broad searches of English-language news because it is blind to wire stories. Wire-service blind spots in news archives can be a substantial limitation.
Weaver et al. (Mon,) studied this question.