Researchers at the Georgia Institute of Technology have created a Covid-19 Event Risk Assessment Planning Tool to help policymakers, event planners, and individuals understand the risks associated with in-person gatherings of different sizes throughout the United States.

The  free, interactive map provides the current risk level for each county in the U.S., based on the size of the group and the location. They define the risk level as “the estimated chance, from 0 percent to 100 percent, that at least one Covid-positive individual will be present at an event in a county, based on the given size.” The map is updated daily with the latest information on reported cases in every county across the U.S., and assumes that the actual number of coronavirus cases is up to 10 times higher than what’s in the official reports due to lags in testing and reporting.

The risk assessment tool is primarily useful for local meetings which do not include attendees from various locations. It also can’t take into consideration how well people are following protocols, such as wearing masks and social distancing. It could be helpful when planning a hybrid meeting with a centralized virtual location and satellite events being held in person.

“In a way it’s like a weather map,” said Clio Andris, a professor of city and regional planning and interactive computing at Georgia Tech, who worked on the project. “It can tell you what the risk is that it will rain, but it can’t tell you if you’ll get wet. That depends on if you carry an umbrella, or if you choose not to go outside at all.”