MIT researchers: Lack of reopening coordination comes at a cost

People's adherence to COVID-19 shelter in place orders is influenced by friends and family even in other states, according to a new working paper. For that reason, researchers said failure to coordinate the lifting of such orders comes at a substantial cost.

The paper, released Thursday by the Massachusetts Institute of Technology's Initiative on the Digital Economy, found that people's behavior in a given area is "significantly influenced" by policies and behaviors in other, sometimes distant, regions because of their social interdependence. When just one-third of a state's social and geographic peer states adopt shelter in place policies, it creates a reduction in mobility equal to the state's own policy decisions, the paper found.

"A surprising finding of the study is that it's not just geographic spillovers, but that the social spillovers that sometimes happen at great distance matter a lot in terms of how behaviors in one state affect behaviors in other states," said Sinan Aral, director of the MIT's Initiative on the Digital Economy and an author of the study.

The paper aligns with findings that show an increasing reliance on social media to stay in contact with loved ones during the pandemic. Almost three-quarters of Americans said they view social media as important for staying connected during the pandemic, according to a poll released Thursday from Gallup and the Knight Foundation, and one-quarter said they've used it more since the pandemic began. Nearly half of survey respondents said most or almost all of the content they see is about the coronavirus.

Aral said the MIT paper has been submitted to a major journal, which is currently conducting peer review. The journal, which Aral declined to identify, agreed to allow the article to be released early given its timeliness, he said.

The study used county-level data on shelter-in-place orders with movement data from more than 27 million mobile devices, social network connections among more than 220 million Facebook users and weather and population data to estimate both geographic and social network spillovers created by regional policies nationwide. The study tracked data between March 1 and April 18.

Researchers included charts with the top 20 states that influence its residents the most through a combination of social and geographic factors.

"What these coordination maps give governors is sort of a back of the envelope way to know which other states they need to be coordinating with in the absence of national guidance on coordination," Aral said.

The data show Florida is most influenced by New York, despite the great distance between the states. New Hampshire has a strong influence on adjacent Massachusetts, despite being a small state. Perhaps unsurprisingly, Georgia is most influenced by neighboring states through travel. The week after Georgia reopened, the University of Maryland estimated more than 500,000 people entered the state from neighboring states to visit businesses that were open there but not in their own states.

The findings show that where geographic spillover is high, one state might have to compensate for a neighboring state's loose restrictions by implementing stricter rules that it would have otherwise been necessary, Aral said.

"So if I'm the geographic or social neighbor of a state that's having lax policies, I—in order to get to the social distancing I want to achieve—have to be even stricter with my own citizens," he said.

By contrast, when states coordinate, social and geographic spillovers actually help them achieve their targets more efficiently because they essentially provide "free treatments" as the cooperative behaviors of peer states positively influence social distancing behaviors in other states, the study found.

Previous research has linked social contagion in behaviors like exercise, the use of certain products and voting. Given that, the researchers said it's likely that people's adherence to social distancing policies are affected not only by the policies in their own area, but by those of neighboring regions and those in which their social contacts reside.