Is it true American news doesn't report mass shootings under 16 people?

This is one of my rare serious questions. A friend argues in America mass shootings aren't reported by the media unless at least 16 people have been shot. Personally I'm skeptical on this so I thought I'd ask you lot.
What is the minimum size shooting before it makes local, state and countrywide news?
Do shooters see that number as a goal?
Is it true American news doesn't report mass shootings under 16 people?
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