Emily Oster

7 minute read Emily Oster

Emily Oster

COVID: Risks & Benefits Matrix

Emily Oster

7 minute read

If you follow me on Twitter or Instagram, you will have seen some frustration/snark/anger this week around schools. I think kids really need schools. I think parents need schools. I think the economy needs schools. And based on data from Europe and elsewhere, I think it is possible for a society to open schools relatively safely.

BUT: I am also very much in favor of public health and worried about COVID-19. And I’m basically in a demoralized place of feeling like it may not be possible for this society to open schools safely.

Earlier this week, in thinking about this, I was mad. It feels, at least to me, like we have our priorities wrong. For example, Disney World is open and schools may stay closed. I “articulated” this is in an all-caps angry Tweet (everyone know this is the best way to make yourself heard).

Then I went running, and calmed down, and tried to think about why I was so mad. Was there a clearer way to express these frustrations? What is it about opening Disney that set me off?

I’ve been seeing versions of this risk graph around a lot. It lines up activities in terms of their COVID risk — opening the mail and playing tennis in the least risky group, sporting events and bars at the top. I like this graph, and I think it can be useful in guiding both individual and policy choices. It is helpful in asking both what activities you should do, and also what activities policymakers should allow.

Choosing activities closely relates to the idea of a “risk budget”. As others have noted, our societal goal is not to reduce all risks to zero (we wouldn’t have cars, or pools, or many other things), but there is a limit to the level of risk we are willing to adopt. It is appropriate to be willing to take on some risk of COVID-19 transmission, but not infinite risk.

So: let’s imagine we have a risk budget, and we’re faced with these risk-ranked activities. If your goal was to allow (or do) as many activities as possible, you’d allow the lowest risk activities first, and then add on until you hit the budget.

But this focus on risk alone misses something very fundamental: benefits. These activities do not all have the same benefits, to individuals or to society. For example, this chart ranks grocery shopping as more risky than playing tennis. Probably true, but the benefits are also considerably higher. Similarly, going to a shopping mall is lower risk than child care and school in these rankings, but I’d venture many people would perceive the benefits of school as higher.

In fact, our goal is not to get the most activities allowed with our risk budget. Instead, it is to have the highest total benefit subject to the risk budget. This is true both of us personally and of society. To make good decision with that frame, it’s not enough to have the risk graph. We need to think about these risks along with benefits. Basically, we need two axes.

Here’s a simple version of a two-axis graph, capturing the risk levels in that link above, and my own personal preferences. There are some activities that are very important to me but also high risk, like seeing grandparents and having child care. There are others which are high risk and very unimportant to me, like bars (I have little kids; my bar days are over). And then there are low risk/high benefit activities (hiking) and low risk/low benefit activities (biking; I hate it and usually get badly injured).

For me, this is useful in thinking about things I definitely want to do (hiking) and definitely do not want to do (bars). It’s also helpful to think about trade-offs. If our family has a risk budget, we may need to choose between child care and grandparents.

We can make a similar graph for policy, for thinking about where the various activities states could allow fall on these axes. Here’s an example policy graph, where I’ve inserted my own views about the social benefits of these activities (hey, it’s my newsletter!), along with the risks.

If you were a policy-maker with these preferences, things in the upper left quadrant (parks, hiking trails) are probably the first things to open. When you think about moving to open more, and consider which high risk activities you want to allow, the right side of the graph give you a sense of rankings.

Activities in the bottom right quadrant should come after the upper right. They provide lower benefits at the same level of risk. It doesn’t mean you shouldn’t eventually do them (in non-COVID times I definitely support bars and gyms!), but they shouldn’t come first.

Now: I’ve drawn this picture based on what I would do as a social planner. But this is just my opinion. Others will differ. There are reasons to have bars and gyms and we may put houses of worship above schools. If you were the policy-maker, you’d draw a different picture. That’s fine. (For example, I put tennis in as a low benefit but not everyone will agree with that!)

Where I think this framework is helpful, though, is in articulating what we must believe as a society to defend the choices we are making. If we choose to open bars while schools stay closed the only way to defend that, given the risk data, is to say that you think the benefits of bars are much, much higher (perhaps people really enjoy them, or tax revenue). If that’s the case, it could make sense to spend your risk budget on them.

(You should also say you disagree with the risk assessments and, say, think that bars are not risky. This would be inconsistent with public health experts, so would be good to make explicit.)

I think this type of analysis also helps us make sense of some of the dialog around the Black Lives Matter protests in the past months. People were outraged when some policymakers were supportive of these protests, having previously told people not to go out of their homes. It’s right that protesting in a large group, even outside, is riskier than being in your house. But the social benefits of these protests were enormous. High risk, high benefit.

So what does one do with this? Well, on a personal level maybe making one of these could help with your own decision-making (we’re working on a richer, more interactive version for COVID-Explained!).

But, much more than that, I’d like to see this framework articulated in our policy discussions.

In my wildest dreams, I’d like to see each of our Governors give a press conference with a picture like this behind them which reflects their policies. It’s not that these policies aren’t defensible, but I would like to see people say: bars have a sufficiently high benefit that I’m prioritizing that over in-person schooling.

I might still be mad but at least I’d be better able to articulate why.

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