The entire world has adopted different social distancing methods in the wake of COVID 19. It includes bans on large gatherings, school cancellations, restaurant and bar limits, non-essential business closures, etc. In the United States, different states have taken different strategies to keep people in their houses in order to reduce the spread of COVID-19.
Babak Heydari is an associate professor of Mechanical and Industrial Engineering at Northeastern University. He decided to find out which tactics are actually working and encouraging social distancing. Every state of the U.S. has its own policy. Hence, there is a lag in the timing of these policies even when they implement the same one. This creates a kind of natural experiment tested for answering these types of questions. Along with a teammate, Heydari used the dates that states implemented various policies to analyse data released by Google that showed how much people moved around on a daily basis in the month of March. The first thing to be noted was that people started staying home even before they were told to. News of the outbreak spread faster. In early March, many people began to change their behaviour voluntarily. The researchers needed to separate out these actions, as well as account for weather, days of the week, and other factors that might affect how much the average person travels. It was found that some policies worked better. The most effective social distancing policy is the stay-at-home policy. It is six times more effective, in terms of reducing mobility, compared to not doing it. Other social distancing policies, like the closure of non-essential businesses, restaurants, and bars, showed a smaller, but still significant, impact.
However, the rest of the policies, like large-gathering bans and school closures, there was a decrease even in the states that have only those policies. On their own, these policies may change people’s behavior. However, by the time they were in place, the reduction in people’s movements had already happened.
“It’s too soon to do those analyses, given the prolonged incubation period of the virus. The researchers are collecting data, but policy changes will need to be in place for several weeks before they begin to make a noticeable difference in the infection rate”, says Heydari.
Shahjadi Jemim Rahman