Here is a very lengthy study that I summarized in a one quick paragraph. It was published as part of the Progressive States Network’s Research Roundup.
Local Media Ownership and Media Quality — The Federal Communications Commission funded this statistical analysis of how various media ownership structures affect local usage and programing. There were three policy goals to the FCC’s Review of Media Ownership Rules: gauging competition as measured by local media usage, studying the relationship between local media ownership and local news programming, and measuring the correlation of ownership diversity and media quality. Being evaluated were FCC rules against co-ownership of an area’s newspaper and broadcast channels, limits on ownership of local television channels, and co-ownership of local radio and television stations. Newspaper sales tend to be far more strongly correlated with increased voter turnout than television news programming, so the drop off in newspaper sales over the past few years is alarming from a civic engagement perspective. However, as this analysis of 210 local media markets based on data from the FCC and Nielsen Media Research Galaxy ProFile shows, there is little or no evidence that local media’s ownership structure influences competition or local programming content or quality.