 After I bought that flat toilet paper from Costco, people treat me like I'm royalty, like I'm some sort of Prince Charmin. COVID-19 has done and is doing some heinous stuff. Many healthcare systems are approaching capacity, risking the lives of anyone who might need to go on a ventilator to keep breathing. In an effort to limit the spread and severity of the disease, governments are enforcing quarantine and isolation measures, causing widespread disruption of numerous public services, companies, and the world economy, which hopefully keeps hundreds of thousands of people from dying. I was initially skeptical about how bad it was going to get, but it's bad, and it's probably going to get worse. Of course, in the midst of all this, a lot of people have gone full out prepper in ways that don't really make sense. Some folks are stealing huge boxes of surgical masks from hospitals to keep from getting sick, despite the fact that masks are really only effective at preventing the spread of COVID-19 to others, and doctors kind of need them to keep doctoring. People are buying enough toilet paper to last them until the sun burns out, essentially turning their closets into warehouses for the stuff, while leaving stores totally empty for those who might have actually needed some. The list of things that have been cleared out in this fashion by zealous hoarders also includes pasta, thermometers, and, because of course they are, firearms and ammunition. On the flip side, there are those who are obviously in denial about the state of affairs, which, until recently, included your pathologically optimistic host. In the midst of executive orders banning travel and shelter-in-place decrees from regional governments, tons of people are showing up to large gatherings, restaurants, trade shows, and concerts, vastly accelerating the spread of the disease and thumbing their collective noses at the concerns of epidemiologists who are tearing their hair out in frustration and screaming, you had one job! The divergence of these responses to the threat and reality of COVID-19 echoes several other disasters. According to a 1993 study by Gary McLellan and colleagues, rare but devastating scenarios tend to polarize people into two general groups. Those who focus on the high-risk part of the equation, who might spend significant quantities of time and money to be ever more ready for disasters that never actually happen, and people who focus on the low probability part, who may refuse to take even the most trivial measures to hedge against such events because they're just certain they won't suffer any substantial consequences. It's pretty clear that both extremes are irrational. It's foolish to go to spring break in the middle of a pandemic, as it is to blow your entire savings on a bunker in the woods, just in case. But finding a rational middle ground is harder than you might expect. Catastrophes are hard to predict in many irritating ways. Because they're rare and frequently happen under unique circumstances, it's difficult to nail down any meaningful pattern in their occurrence or impact. Even experts who have studied epidemiology for decades have to put giant error bars on any prediction of the future of COVID-19, simply because it's novel. You've never seen anything like it. Maybe it'll mutate and re-infect the global population every year like influenza, killing hundreds of millions. Maybe we'll discover a decent vaccine tomorrow and distribute it with incredible efficiency to stamp it out. The course of events could easily be tipped one way or another by a staggering number of factors, from infected individuals choosing to stay home to the weather, making any predictive model highly volatile and many wildly different projected outcomes equally likely. Organizations like FEMA or the WHO regularly deal with these sorts of disasters and have some reasonable recommendations for low hanging fruit intended to reduce risk and ease the burden on relief efforts by shifting some responsibility to the affected populace. Get a flashlight, keep some water and non-perishable food in the house, and you'll make things a little easier come hurricane season. But as the costs of optimizing for preparedness go up, both for individuals and communities, the trade-offs necessary for additional readiness become increasingly uncomfortable to justify. Would you rather have two weeks of non-perishable food or 10 cubic feet of storage space and $1,000 to pay off your credit cards? Would you rather have a rescue helicopter and a dedicated pilot on standby or a dozen more teachers? Not to mention that these investments don't sting quite as much for folks who are a little better off. It's hard to justify buying water purification tablets just in case when you're living paycheck to paycheck. Worse yet, the recommendations of even top-notch disaster preparedness organizations aren't really backed by any rigorous evidence. It's a reasonable notion that a community that's equipped with these supplies might exhibit particular resilience against catastrophe, but we've never really seen that idea work per se, partially due to the very small number of people who actually make and maintain emergency kits and partially due to the idiosyncrasies of each crisis limiting the effectiveness of such kits. It's well and good to have a few days of food and water on hand if you're likely to get snowed in. But if someone needs an air filter during wildfires or a mask during the COVID-19 pandemic or a chainsaw during the ant uprising, they're going to be in the same desperate boat as everybody else. Short of a Batman-style utility belt of highly specific emergency apparatus complete with bat shark repellent, it's hard to fault folks for not buying that investing in a go bag is going to do them any good. So how can we tell how much we ought to invest in disaster preparedness? How do we know when those trade-offs aren't really worth it anymore? I guess what I'm asking is, how prepared is prepared in, no, would you look at that? Yes, unlike last episode, I was actually able to run down a paper asking the relevant question this time and in a way that's worth applauding. Many publications of the area of disaster preparedness are content with making vague claims about how being properly prepared for disasters is very important and saves lives, trying their best to sell policymakers on the value of such efforts. But Yong-Yong and friends take a bolder stance, doing some simple analysis to verify the intuitive conclusion that I gestured at, that it's simply not economically justifiable to build disaster response infrastructure that will always be ready for anything. They point to an example that's fairly relevant to our current situation, employing enough doctors to fully account for all of the rare spikes in patients means that you're going to be wasting tons of money the rest of the time. With that out of the way, they attempt to find some sort of framework for asking the right question about how far we should go in preparing for the worst, which nets an interesting approach. Rather than asking how many rolls of toilet paper or how many helicopters you need to avoid any possible shortfall, an impossible question to answer, they ask how frequently an emergency system has to fail due to unforeseen circumstances before the cost of human lives exceeds the cost of maintaining the service. That might sound brutally Machiavellian, but remember that dollars spent on showing up against potential disaster are dollars not spent on public health programs or other immediate life-saving measures. This isn't asking us to abandon people to die. It's asking when spending money on disaster prepping is killing more people than it's saving. Using a range of estimates for the economic costs of a person's death, the authors find that a decent target for the frequency of events exceeding the normal scope of a hospital's operation should be around once a decade. That hospitals should only fail to operate in their standard capacity about once every 10 years. That's an achievable and readily defined goal. If you just look at the peak numbers and frequencies for various types of disasters, you can easily figure out where to set a threshold value for number of doctors on staff, number of beds, stock of antibiotics and so on, such that only a once in a decade catastrophe will overwhelm the hospital's capacity. Note that this avoids the usual issues of predicting what the specific nature and severity of a novel disaster scenario might be. It doesn't matter if the hospital doesn't have enough beds or gets cut off from the main road or gets buried in volcanic ash or whatever. The only thing we're shooting for is that that sort of thing only leaves them unable to care for all their patients effectively once in 10 years. Similar models can be built for different sorts of emergency services like police departments or fire departments, using different estimations for the cost of a failure and how often those failures can be tolerated before you're losing ground against prep work. They also advance an idea of portfolio management as a way of hedging against limitations in preparation. If a sudden spike in patients can be partially or fully offloaded to other hospitals with some room, you can reduce the risk of an event leaving people without treatment. Normally, hospitals compete with each other for patients, but there's a well-established procedure in disaster scenarios for cascading overflow called medical surge, where the hospitals nearest the disaster offload all their patients who can travel to nearby hospitals, who also offload all their mobile patients. During 9-11, that medical surge procedure worked exactly as intended in the New York City area with the cascade reaching hospitals up to 50 miles away, conjuring additional capacity where there was none before. Of course, if everywhere gets flooded with patients all at once, even the most diverse portfolio will take a hit, so please flatten that curve, yeah? Now, obviously, when you're talking about yourself or your loved ones, there's probably no number you can consciously put on keeping everyone safe and healthy, which makes it hard to ask a question like, how often can you tolerate a failure in your disaster preparedness before it's no longer worth investing in? But looking at it as a question of, how often am I okay relying on some outside source of aid to make it through some bad situation? Well, that's more tractable than trying to be ready for any possible emergency. It's still a very subjective question to be sure. Your answer depends a lot on how much you think people around you might lend you a hand if you need it, whether they'll be in a position to help you, and if the answer is no, whether prepping for such a situation would be of any use anyways. Still, the portfolio approach is a good reminder that cooperation and sharing risk and resources are really the best investments you can make in tough times. If you've got a closet full of toilet paper or six months of hot pockets in your freezer, maybe offer some to neighbors if they need them. After washing your hands, of course. Is this sort of economic approach to disaster preparedness Machiavellian, or is it good sense? Please leave a comment below and let me know what you think. Thank you very much for watching. If you happen to be in quarantine or doing the shelter in place procedure, there is a thunk discord with a lot of very cool people who would be happy to chat with you during this time. The link is in the description and up here. Thank you very much for watching. Don't forget to blah, blah, subscribe, blah, share. Wash your hands, stay safe, and don't stop thunking.