Still, measuring how a single set of stories can influence what gets discussed online is no easy feat.
Researchers can't control the news. And if they can't do that, how can they run an experiment?
To help them get started, the investigators enlisted the help of Jo Ellen Green Kaiser, executive director of The Media Consortium. Her group is an association of mostly small, independent news outlets and includes publications like Grist, Ms. magazine and The Chicago Reporter.
Green Kaiser, who previously worked as an editor at the progressive Jewish magazine Tikkun, knew that journalists would not sit on a breaking news story, even for the sake of science. But she thought they might be flexible with some of their feature stories that were not tied to a specific event and thus could run at any time.
"Any good editor worth his or her salt has feature stories stowed away for dry periods when you don't have any news," she said. "We realized we could randomize the timing of those stories. So the intervention was not about the content. It was about the timing."
It took three years of negotiation, but the researchers and journalists from 48 news outlets finally agreed on a study design.
They worked together to come up with a list of 11 broad topics -- such as immigration, climate change, race relations and education policy -- that the news organizations were either covering or were interested in covering.
Next, a set of two to five outlets volunteered to publish stories on the same topic on their websites at the same time.
The journalists were in charge of deciding what story they told, and how they told it. However, if the end result strayed too far from the original topic, the researchers could decide not to include it in the experiment.
If a story simply didn't come together, the outlets could pull out of that particular experiment.