The Newspaper Preservation Act of 1970 is frequently viewed as a legislative device for averting the failure of a competing metropolitan daily newspaper and is said to create, for the formerly competing newspapers, a monolithic management unit which enjoys advantages over the two publishing units it replaces. A study examined one of those advantages--control of circulation of the two papers in ways that enhance the appeal to advertisers of the two newspapers in combination --by analyzing the circulation patterns of two newspapers involved in a Joint Operating Agreement (JOA). The case reviewed is the Seattle, Washington, metropolitan newspaper market dominated by a JOA between "The Seattle Times" and "The Seattle Post-Intelligencer" since May 1983. Results showed that (1) distant"fringe" cities have been lopped from the circulation map; (2) cities of intermediate distance from the publishing plant are targets for circulation building by the Seattle newspaper which does not face direct time-cycle competition from a suburban daily; and (3) circulation is being maintained and increased for both newspapers in the nearby cities essential for the broad area coverage offered to advertisers. No matter what the management form, however, newspaper use among adults continues to decline. (Thirteen extensive notes, one map, and three tables of data are included.) (MS)