Saturday, 22 May 2021

Incentivising coronavirus vaccination

A couple of weeks ago, my ECONS102 class covered externalities. An externality is the uncompensated impact of the actions of one person on a bystander. Externalities can be negative (and make the bystander worse off), or positive (and make the bystander better off). One of the examples I use for a positive externality is vaccines. A person who gets vaccinated makes themselves better off (by reducing their chance of getting sick), but also makes others better off (because there is at least one fewer person who they can get sick from) - that's a positive externality.

The problem with positive externalities is that the market, left on its own, will not ensure that enough is produced or consumed. That's because the market participants don't have an incentive to take into account the benefits that their actions confer on others. That market will produce too little, compared to the quantity that maximises societal welfare. In the case of vaccines, too few people would get vaccinated.

There needs to be some mechanism to encourage more people to purchase goods with positive externalities. One way is to subsidise them (for example, see this post about subsidising education). The subsidy effectively increases the benefits of selling the good or service (if it is paid to the sellers), or reduces the cost of the good or service (if it is paid to the buyers). Either way, it increases the amount that is produced and consumed, and can ensure the quantity is increased to the socially optimal quantity.

Alternatively, the government could find some other way to incentivise more production and consumption. Right now, we're in a situation where governments want to roll out coronavirus vaccines in the face of a substantial amount of vaccine hesitancy. Some governments have started to incentivise vaccines through more than just subsidising them and making them available for free. For example, the New York Times reported last month that:

West Virginia will give $100 savings bonds to 16- to 35-year-olds who get a Covid-19 vaccine, Gov. Jim Justice said on Monday.

There are roughly 380,000 West Virginians in that age group, many of whom have already gotten at least one shot, but Mr. Justice said he hoped the money would motivate the rest to get inoculated, as “they’re not taking the vaccines as fast as we’d like them to take them.”

Some people worry that giving monetary incentives reduces intrinsic motivation. Indeed, this famous research by Uri Gneezy and Aldo Rustichini (ungated version here) showed that fining parents for picking up their children late from a childcare centre encouraged more late pickups. When the moral incentive to pick up on time is replaced by a financial incentive, it turned out to be less effective. The corollary for vaccines is that paying people to get vaccinated could encourage fewer of them to do so.

However, to counter that argument UCLA has run some experiments showing that monetary incentives are effective, as reported by the New York Times a couple of weeks ago:

In recent randomized survey experiments by the U.C.L.A. Covid-19 Health and Politics Project, two seemingly strong incentives have emerged.

Roughly a third of the unvaccinated population said a cash payment would make them more likely to get a shot...

Similarly large increases in willingness to take vaccines emerged for those who were asked about getting a vaccine if doing so meant they wouldn’t need to wear a mask or social-distance in public, compared with a group that was told it would still have to do those things.

So, perhaps we don't need to worry so much about whether the monetary incentive would be effective. And, perhaps we wouldn't have to pay it to everyone. CBS News reported yesterday:

Health officials in Ohio have reported a surge in the amount of people getting their first COVID-19 vaccination shots, a week after Ohio Governor Mike DeWine announced the $5 million "Vax-a-Million" lottery.

Just days after DeWine said the state would award five vaccinated residents $1 million each in order to raise vaccination percentages, the Ohio Department of Health reported more than 113,000 people received their first dose of the vaccine.

Based on preliminary data, the department said the recent period showed a 53% week-to-week increase (May 13 to 18) compared to the time period before the announcement, where 74,000 people received their first dose (May 6 to 11). 

"We are seeing increasing numbers in all age groups, except those 80 and older, who are highly vaccinated already," said Ohio Dept. of Health director Stephanie McCloud. "Although the rate among that group is decreasing, it is doing so at a less rapid pace, demonstrating some positive impact even in that group."

Ohio residents 18 and older who have received at least one dose of the vaccine can enter to win one of the five $1 million prizes. Ohioans between the age of 12 and 17 who have received at least one dose of the COVID-19 vaccine can enter to win one of five four-year, full-ride scholarships to any state college or university in the state. So far, approximately one million entries have been collected, according to Ohio Lottery and Ohio Department of Health.

Gamifying vaccination by attaching it to a lottery is kind of inspired. If people who are the least risk averse are those who are least likely to get vaccinated, and also those who are most likely to play the lottery, then this could be incredibly effective in increasing vaccination rates. People constantly overestimate the chance of events happening that have small probabilities (this is one of the key features of what is called prospect theory), like winning the lottery. So, government wouldn't necessarily have to ensure that the lottery amount was high enough to ensure that it captures all of the social benefits of vaccination, making this solution more cost effective than paying everyone who got vaccinated. For example, paying 100,000 people $100 each to get vaccinated costs $10 million. But, government could possibly offer five prizes of $1 million each and get the same outcome of 100,000 people getting vaccinated for half the total cost.

Overall, New Zealand's approach to vaccination is slow and steady. We're ahead of target (see the New Zealand Herald's Vaccine Tracker), but there is a fair amount of concern about whether we will achieve the overall target (e.g. see comments here or here). There seems to be plenty of demand for vaccines right now, but if things start to slow up later, perhaps we need our own vaccine lottery?

[HT: Marginal Revolution for the NY Times article on incentives; The Dangerous Economist for the article on Ohio's lottery]


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