"Reliable Sources" in Cable News: Analyzing Network Fragmentation in Coverage of Reform Policy.

News coverage of the Patient Protection and Affordable Care Act (PPACA) and President Obama's announced Clean Power Plan (CPP) served as data for two case studies. Social network analysis was used to investigate the sources used by cable giants CNN, Fox News, and MSNBC. Both case studies show the extent of sourcing varies across the three news outlets, with CNN using the smallest network, MSNBC using the largest, and Fox falling somewhere in between. Ultimately, the source networks of the three cable outlets were highly fragmented with the exception of high-profile politicians. While the number of sources used in PPACA coverage stayed relatively stable, sourcing of the CPP decreased over time. Results suggest different sourcing patterns and contextually driven agenda-building processes.