A study quantifies the trade-off between danger and necessity when reopening businesses. It found that gyms should be last priority.

• All US states are allowing businesses to reopen, but some pose more risk for coronavirus transmission, and are of less economic importance, than others.
• A new study evaluated which kinds of businesses offer the best value trade-offs.
• It found that banks were at the top of the chart, followed by department stores and dentist offices, since employees can social distance and wear protective equipment.
• Working out at the gym, however, poses unique risks, including crowds, highly touched surfaces, and people breathing heavily without masks.

Reopening businesses and lifting lockdown restrictions is inherently a question of trade-offs. Leaders and public-health authorities must evaluate how much people need a particular type of business and how valuable it is to the economy, relative to the risk that people could catch the coronavirus by visiting that kind of establishment.

A new study from researchers with the MIT Initiative on the Digital Economy created a rubric to determine which businesses, from hardware stores to banks to gyms to restaurants, make the most sense to reopen first.

The research, published this week in the journal Proceedings of the National Academy of Sciences, found that banks offer the best value trade-off. Department stores and dentist offices could reopen shortly after banks, the study suggests, as long as they follow social-distancing measures and employees wear masks.

Gyms and cafes pose the most risk, the researchers found, while liquor and tobacco stores also offer few valuable social services. So all of those businesses should have some of the tightest restrictions, the study concluded.

"Locations like gyms both emphasize physical contact and make mask use unpleasant," the researchers wrote.

Trade-offs of risk and economic necessity

The new study evaluated the "danger index" — essentially the risk that visitors could catch the coronavirus — for auto shops, banks, cafes, colleges, dentists, gyms, and places of worship. It also looked at a variety of stores: those that sell clothing, electronics, furniture, hardware, liquor, and sporting goods.

The coronavirus typically spreads via droplets when people are in sustained, close proximity. Enclosed spaces, crowds, close contact with others, and difficulty social distancing all raise the risk of that happening.

The researchers used nine criteria to evaluate the average risk level of various businesses. They estimated total visits to that kind of place, unique visitors, time spent at the location while there is moderate crowding, and time spent at the location with high crowding. Then they evaluated those four factors separately for individuals over the age of 65, who face a higher risk of severe coronavirus cases. They also factored in the average distance traveled to the business location.

Then the researchers evaluated the value of the social service that these businesses provide. That value assessment was based on national consumer preference surveys, as well as economic statistics such as how many people stores employ and how much money people spend at them.

Then they compared the danger index against the service's value.

"The core idea is that locations offering better trade-offs should face looser restrictions," the researchers wrote.

They found that banks should open first, while gyms should go last

The researchers found that banks and other financial institutions offer the best trade-offs. They are relatively low-danger, and using them is critical for many people.

The researchers suggested that general department stores such as Walmart or Target, dentist offices, auto shops, and even colleges could reopen after banks. That's because those businesses have a high share of workers who don't need to be close to visitors, which makes social distancing easier.

Among retail stores, the researchers found that electronics stores and furniture stores should be opened before liquor, tobacco, and sporting goods stores.

Gyms, cafes, sporting goods stores, liquor and tobacco stores, and bookstores don't offer valuable trade-offs, either because they can get crowded, because people spend longer inside them, or because they are of lower social and economic importance, according to the study. So those businesses that should face relatively "tight restrictions," the researchers wrote.

Such restrictions could include mandatory mask wearing and curbside pickup where applicable.

The researchers also wrote that that the trade-offs they analyzed were about the same in both rural and urban areas, "suggesting that the urban-rural divide is not an important dimension for policymakers."