We’re starting to reach a critical stage in the vaccine rollout. Less than half of U.S. adults have received one dose of a COVID-19 vaccine and only 35% are fully vaccinated. And some experts are saying it’s unlikely we’ll ever reach herd immunity.

Now local governments are partnering with businesses to offer incentives, free stuff in exchange for getting the vaccine. But do these programs work?

The mission to get more vaccines into people’s arms is starting to take on a bit of an Oprah Winfrey vibe. West Virginia is giving $100 savings bonds to people 16 to 35. Maine is offering free hunting and fishing licenses. And in New Orleans, a pound of crawfish.

“Incentives are nice because they’re the carrot approach. They’re leading people toward something in a positive way,” said Noel Brewer, who researches vaccination behavior at the University of North Carolina. Brewer said incentives appeal to people across party lines. And studies show they increase vaccine uptake by about 8% — if the incentive is of value.

“There are costs and benefits to any action, and a person engages in the action if her perceived benefits exceed her perceived costs,” said Mario Macis, a behavioral economist at Johns Hopkins University.

Costs could be literal, like transportation to and from a vaccination site; the Biden administration has partnered with Uber and Lyft to provide free rides. 

But benefits can also offer people something they want. New Jersey is running a “Shot and a Beer” program. Macis said this can make a needle in the arm seem fun “because they might go with a friend of a group of friends and get vaccinated together and then go out and get their free beer.”

And incentives like New York’s free tickets to a Mets or Yankees game also whisper freedom. Like, “Hey, remember when we high fived strangers after home runs without fear?”

Gretchen Chapman, who studies vaccine behavior at Carnegie Mellon University, said incentives usually work on people who only need a little push. And researchers don’t know if they’ll work for the COVID-19 vaccine like they have for others.

“We’re at the point where there’s going to be no one intervention that’s going to meet everyone who hasn’t vaccinated yet,” she said.

So governments will continue to increase accessibility and attractiveness until experts say they move to create mandates where they can.