States that have reopened bars experienced a doubling in the rate of coronavirus cases three weeks after the opening of doors, on average. The Post analysis — using data provided by SafeGraph, a company that aggregates cellphone location information — found a statistically significant national relationship between foot traffic to bars one week after they reopened and an increase in cases three weeks later.

The analysis of the cellphone data suggests there is not as strong a relationship between the reopening of restaurants and a rise in cases, nor with bar foot traffic and cases over time, except for a handful of states.

But like with so much in the pandemic, easy answers can prove elusive.

A study by the Centers for Disease Control and Prevention of nearly 300 adults who tested positive for the coronavirus found that they were more than twice as likely to have dined at a restaurant in the two weeks before getting sick than people who were uninfected. Those who tested positive and did not have close contact with anyone sick were also more likely to report going to a bar or coffee shop. The same effect was not seen in visits to salons, gyms and houses of worship, or in the use of public transportation.