Story selection --let me expand on my point.

Every media outlet chooses which stories to cover and which stories to highlight. A media source may ignore some issues and be obsessed with other issues.

Classically speaking, the media select stories based on impact, timeliness, proximity to the audience, conflict, human interest, novelty, etc. These elements are summarized in many places, including here: http://www.studylecturenotes.com/journalism-mass-communication/elements…

This challenge can be mitigated by reading a variety of sources. But some issues are chronically underreported because they are boring, happen slowly, lack drama, and cannot be reduced into a simple cartoon. The most underreported stories tend to be good news from a distant land, dealing with ordinary people and not marked by a dramatic event.

Rob