A coalition of consumer groups suggested Thursday that the Federal Communications Commission should review the impact of potential media mergers using a statistical index that suggests much of the media industry is already too consolidated.

Unveiling a series of market-by-market concentration studies with a promise of more to be filed with the FCC on Monday, the Media and Democracy Coalition said media in cities from Los Angeles to Bangor, Maine, either already exceed the Justice Department standards for excessive concentration or would if further mergers are allowed.

“We find that California citizens already face highly concentrated markets with few choices of news and views,” said a California-focused report released by the coalition, whose members include Common Cause, Consumers Union and the Consumers Federation of America. “Possible mergers would only make it worse, risking both localism and democracy.”

Mark Cooper, research director for the Consumers Federation of America, said the FCC should specifically assess the impact media mergers might have on how public opinion will be determined in a market, with viewership and readership of news and public affairs in individual media weighted by impact in examining potential effects.

The group’s comments come as the FCC struggles to determine what’s necessary to maintain competing local voices in reviewing media mergers. The FCC is reviewing its ownership rules in the wake of an appellate court decision throwing out the old rules and also a plan to use a “diversity index” that would have counted The New York Times and a weekly newspaper as having equal impact in determining which media deals would be allowed.

The coalition also unveiled reports Thursday on Texas, Pennsylvania, Michigan, Oregon, Ohio, Washington, Arkansas, Virginia and Maine.

In a statement, the National Association of Broadcasters said it hopes policymakers “recognize the seismic changes in the media landscape in the three decades. Measured relaxation of regulations will preserve localism and ensure that free, high-quality programming enjoyed daily by millions of Americans does not migrate to pay platforms.”

The reports are available at media-democracy.com.