Annalee Newitz:

To be more precise, it only takes three or more stories from small news outlets covering the same topic to make discussions of that topic go up by 62.7 percent on Twitter.

It took a group of Harvard researchers five years to reach this conclusion. They did it by tracking the effects of stories covered by 48 small media outlets, measuring how they affected conversations on Twitter. Harvard political scientist Gary King and his colleagues explain in the journal Science that they honed in on 11 broad topics in public policy, ranging from refugees and race to food policy and domestic energy production.

“If we’d been conducting this study 100 years ago, we would have gone into town squares and listened to what people said on soap boxes,” said King. “Today, it’s Twitter.”