A multi-risk SIR model with optimally targeted lockdown

Or you could say “all-star economists write Covid-19 paper.”  Daron Acemoglu, Victor Chernozhukov, Iván Werning, and Michael D. Whinston have a new NBER working paper.  Here is part of the abstract:

For baseline parameter values for the COVID-19 pandemic applied to the US, we find that optimal policies differentially
targeting risk/age groups significantly outperform optimal uniform policies and most of the gains can be realized by having stricter lockdown policies on the oldest group. For example, for the same economic cost (24.3% decline in GDP), optimal semi–targeted or fully-targeted policies reduce mortality from 1.83% to 0.71% (thus, saving 2.7 million lives) relative to optimal uniform policies. Intuitively, a strict and long lockdown for the most vulnerable group both reduces infections and enables less strict lockdowns for the lower-risk groups.

Note the paper is much broader-ranging than that, though I won’t cover all of its points.  Note this sentence:

Such network versions of the SIR model may behave very differently from a basic homogeneous-agent version of the framework.


…we find that semi-targeted policies that simply apply a strict lockdown on the oldest group can achieve the majority of the gains from fully-targeted policies.

Here is a related Twitter thread.  I also take the authors’ model to imply that isolating infected individuals will yield high social returns, though that is presented in a more oblique manner.

Again, I would say we are finally making progress.  One question I have is whether the age-specific lockdown in fact collapses into some other policy, once you remove paternalism as an underlying assumption.  The paper focuses on deaths and gdp, not welfare per se.  But what if older people wish to go gallivanting out and about?  Most of the lockdown in this paper is for reasons of “protective custody,” and not because the older people are super-spreaders.  Must we lock them up (down?), so that we do not feel too bad about our own private consumption and its second-order consequences?  What if they ask to be released, in full knowledge of the relevant risks?


Sorry for the trolly comment but this is one of the very few instances on this blog of the annoying use of “again” which is popping up in written and verbal communication with increasing frequency.

By 'with increasing frequency', do you mean again?

This wins today.

Frequency of goodness is best when Republicans have absolute power over the world.

"For baseline parameter values": what does "baseline" mean here? Something to do with the economy? Something to do with the epidemic? Or something to do with implying that anyone using different values is being a bit of a heretic?

At least they came to the same conclusion as my Uncle Ek.

Progress in the U.S. is apparently measured differently - An influential coronavirus model often cited by the White House is now forecasting that 134,000 people will die of Covid-19 in the United States, nearly double its previous prediction.

The model, from the Institute for Health Metrics and Evaluation at the University of Washington, had predicted 72,433 deaths as of Monday morning.

I have many questions about this paper. It seems important, but I can't tell how well their MR-SIR model actually does in estimating/fitting what has already happened, which doesn't make me confident of it's predictions.

There's also this statement, "Consistent with our aggregation result, the figure shows that the overall infection rate peaks around 6% early on and follows the hump-shaped pattern typical in SIR models." 1) That last phrase basically saying our picture matches other pictures is just hilarious and reflects these researchers lack of comfort with this model. 2) Infection peaks at 6%... son... this thing is everywhere already. Antibody testing suggests that infections are well past that figure. The first death in France from Covid was in December. If this is your model, take it back to the drawing board. Tyler says we are finally making progress... I'm unclear what definition Tyler is using for progress.

What percentage of deaths in the less than 40 cohort are a function of bad genetics rather than bad health-co morbidities? BMI? I think answers to those questions are relatively important.

I think it’s some related to allergies. Either to the virus itself, antibodies, or something like that. Thus why famotidine and antihistamines are starting to show preliminary evidence as a treatment. But really I don’t know.

Now related to the post... do we really think the 60+ And other at risk folks are going to be able to bunker down until a vaccine is developed (if one is) or until this thing runs its course by end of 2021 or 2022?

I think this approach (even if it is the best) sucks. I don’t think it’s going to be sustainable.

I am finding myself falling back into pessimism today. By the time this runs its course a million plus are going to be dead and the economy is still going to shellacked.

We just can’t seem to get Ro low enough in these here United States and the boomers are not going be able to bunker down for 2 years.

I am praying for a vaccine or treatment. If not... yikes!

And now with the murder wasps (half joking... actually 90% joking)... it feels like the biblical plagues.

Get out your lambs blood folks.

"murder wasps"?!?

The U.S. should welcome all life forms from Asia. All these wasps want is to make a better life for themselves here. You must shed your xenophobic and anthropocentric attitudes.

Touché man. But point to some evidence in global history of innovation and growth not being tied to immigration and I will adjust my views.

Seems as tho open societies and a mixing bowl of ideas has always been a boon for the society.

Name one point in US history for example where immigration has been a bad thing? U go back to Columbus maybe?

> Name one point in US history for example where immigration has been a bad thing?

Have you ever hung drywall for a day? It will cause a modern 24 year old that is fit to complain like you've never seen before, because it is godawful, backbreaking labor. Few jobs compare.

It used to pay well above **median** wage. Precisely because it was so hard and few could do it.

Today, thanks to immigration, it pays below minimum wage. How? Because contractors bid on a job, and the hourly is hidden from everyone. The immigrants doing the job sign up for an 8 hour job at $10/hour, knowing full well it will take them 15 hours to finish. That's $5.30/hour. The contractor doesn't care if they were there until 9 PM to finish.

Meanwhile, the pretty blond 18 year old doing a job that took 30 minutes to learn is selling hamburgers for $15/hour solely because she speaks English and is here legally.

In simpler terms, we've watched a job that was worth every penny at $60K/year ($30/hour) collapse to less than $6/hour due to immigrants.

There's your example.

Yes, among the skilled, the more the merrier. We shoudl suck the most brilliant folks from the best universities around the world and bring them here to innovate.

Yes, hung drywall, was a painter, dug pools, assembled wire harnesses, cut grass... Done freaking every job because I had to start working at 13.

Btw, did it for 4.25 an hour because that’s what they paid pond scum like me back then.

And for the record, no job has really gone from 60k a year to 6 bucks an hour... that’s a lie and u know it.

Link 1) is an LA Times article explaining that construction jobs paid $32/hour (today's dollars) in 1972. That's $64K/year. And since you've done drywall, you know it's requires a fair bit of skill--more than framing--and it's much, much harder work than framing. Ditto with masonry.

Link 2) talks about drywalling today, and explains $40K is realistic today, but $60 to $90K in good times is doable.

Thus far, we know that historically AND TODAY that legal drywall has paid well.

Link 4 explains how the companies are set up to insulate big home builders and large construction firms from the use of illegal immigrants. It goes into great detail on the economics, including moving illegal employees to piece work instead of hourly. On page 24, they outline the bidding process, and how Mexican bosses bring in other Mexican workers who take whatever the Mexican boss pay, without complaint or raises.

And on page 3 of that umass study, they indicate 25% were paid less than the minimum wage and got no OT payment. Remember, the average wage in Mexico is $2.60/hour. If you think earning $6/hour without any taxes or witholdings is a step down, you are wrong.

At this point, it should be very clear to you that a legit and legal drywall contractor has always been able to make $60K/year--certainly above median wage.

And at this point, it should be very clear to you that throngs of people are coming across the border and working at below minimum wage for a task that historically requires payment at 4X the minimum wage.

Apology accepted.

1) https://www.latimes.com/projects/la-fi-construction-trump/
2) https://lancasteronline.com/news/why-drywall-attracts-illegals/article_84a10d8d-8f5d-580d-afe5-18c5f1031db8.html
3) https://www.umass.edu/lrrc/research/working-papers-series/wage-th

That was almost 50 years ago. I thought you were talking about within someone’s actual career. It took about a week to get it down. Ceilings a little longer.

In 2070 robots are knock profession out completely.

Things change in half a century.


You aren't understanding....drywalling paid above median wage in 1972. And if you are doing it by the book in the US it will can. But there's a huge glut of immigrants doing it today for less than minimum wage. Which is precisely what I said originally, and which is what you said was "a lie".

Fact: There is a job, drywalling, which commands a market wage well above median income when done legally. That has been true for more than 50 years.

Fact: There are immigrants that are doing that job IN LARGE NUMBERS IN THE US for below minimum wage.

You said to name a point where immigration has been a bad thing. The two points above should make it clear if you are a drywaller (or any other semi-skilled worker), illegal immigration is putting serious pressure on your ability to earn a reasonable living by flooding the market with people that are willing to work below minimum wage

If total coronavirus deaths are 0.2% of population, in US that would be 700.000 deaths.
If of those deaths 5% are younger than 50 years, that would represent 35.000 deaths of younger Americans
When debating what to do, why has such vital age related data been so much ignored?

Damn herd immunity at 100 percent infection? That seems high....

Also by taking a look at BMI and co morbidities, one could argue that the young with those risk factors arent safe and should bunker down in the same way that the elderly do.

High BMI and co morbidities should equal automatic quarantine regardless of age.

If every obese person in America bunkered down with the oldies, there would be nobody to run the economy.

Not everybody is obese. Just 60% of us.

Listen to yourself. You're saying we should force these people to stay home not because they are at risk of spreading the disease, but because they are at risk of dying from it. That logic is the death of liberty. In a free society your power to coerce people to save their own lives is necessarily limited. The libertarian solution would be to make it easier financially for them to quarantine, but note this is more about mortality that total infections. If there were some relationship between being a "super spreader" and dying it might make sense. The fact is most people will get the disease and be fine, and spread it to other people who will also be fine. The only viable option in a free society for a situation like this is relying on informed consent and setting the right incentives. The time for fascism 2.0 is over in my opinion. Time to step back from the abyss.

So just admit that we are a society stuck on some abstract ideas that make it impossible to stop the spread or the deaths, accept out failure, pretend it is a moral success and go make ourselves some money.
Yes, I think that will sell very well.

The WHO organization is saying 300,000 people per day in emerging economics will be dying in the summer and fall if the worlds' biggest producers of food (US and EU) aren't back to normal and once again producing massive excesses of food.

WHO believes millions could die of starvation in just a few months.

Remember, drunk driving kills 10,000 people a year in the US, many in the prime of their lives and many that hadn't been drinking. Heart disease (600K), cancer (600K) and accidents (200K, including drunk driving) round out the list.

In the end, the % of young people (under 30) that are dying from this is <<1%. It's not 5%.

If you met a young person that said they were afraid to drive because they might die in a crash, you'd think they were insane. It's much more insane for a young person to claim they are afraid of catching and dying from covid.

I don't know why we would be producing less food. A) it's an essential industry, so should be free to operate right now. B) the demand for food is relatively constant, it's merely shifted from restaurants to grocery stores. Why would that shift result in less food production?

Google "I pencil" and replace "pencil" with "food". We have a centrally planned economy right now, i.e., one where government decides which economic activities are more essential than others. Indeed, we are now seeing shortages of meat to go along with earlier shortages of toilet paper and "excess" milk being poured down the drain. Of course, each of those supply-chain problems has some identifiable proximate cause other than central planning error. It's just coincidence that they happened to start right after government decided to shut down "non-essential" businesses. The shortages of similar goods in the Soviet Union also were not the fault of the central planners, who always had another five-year plan to fix the problem.

Drunk driving kills 10k a year... but over half of those are driving drunk, and over a thousand of the remaining were sitting in the drunk driver's car. Then there's the pedestrians, which are another thousand. In practice, 1500 people or so are killed in the US every year, while driving a car, when crashing with a drunk driver.

Given that on any given year, Americans drive 3.2 Trillion miles even if we account for a few percentage points of drunk driver miles, we are still talking about one death per billion miles traveled. If we assume 10k miles driven in a year, and we are also very friendly to danger and assume that all those miles are driven at the same risk of encountering a drunk driver as any other (which they are not, as most miles are driven in safe times). your chances of dying from a drunk driver after an entire year of driving are in the order of 1 in a hundred thousand: 0.001%.

So no, the chances of a 25 year old that doesn't drive drunk of dying of covid 19 this year are quite a bit higher than that.
If we go to, say someone in their 40s, they'd be safer if they drove drunk all the time and didn't contact anyone than if we all went out with no precautions. And we give people tickets, and send them to jail, for driving drunk.

> Drunk driving kills 10k a year.

Then take the drunks out of it. We have nearly 30K auto deaths per year that are NOT related to alcohol. We have about 800 kids aged 0..15 that died in a crash that alcohol wasn't involved.

About 1000 people under aged 40 have died from covid. Included in that are 9 people aged 0..15.

If you never leave your house, you won't get covid and you won't die in in a car crash. If you leave your house, both could happen. And if you are 0..15, your chances of dying in a car crash that wasn't your fault is 80X higher than dying from covid .

I'll bet of the 30K auto deaths, at least 20K are under 40. That means you are 20X more likely to die in a car crash that covid if you venture outside of your house.

What's old is new again: the ancient Greek philosopher Socrates (the three word prefix before "Socrates" is for younger MR readers, if any exist) advocated in his Republic that society be relegated into barracks, with children raised by the State. That would be a segregated age-specific way of dealing with Covid-19 as well. From memory, I think Socrates also advocated polygamy or polyarmoury, and I think short hair styles in women. Also a form of eugenics without Googling it. Was Socrates ahead of his time, or have modern times regressed by 2500 years?

I can't tell, from reading this paper, whether this paper makes magical assumptions about aged care workers or not, which usually seems to be the case with "segregate the elderly to allow herd immunity" arguments.

Even with a general lockdown, health care workers still have to go in and out of nursing homes. That’s the case today and nursing homes residents are dying today in large numbers.
With a complete lockdown, they’re just some what less likely to be infected by health care workers since most people are not out and about.
It seems that the only thing required is control of access between 2 groups, one of which has a fixed location.
There are ~ 15600 nursing homes in the US. If on average each has to test 20 workers a day, with a daily cost of administrating test of $ 5000 a day that’s 2.3 B a month vs 1T a month for the shutdown.
300,000 tests have to be performed every day. That should be doable. Give all these places 3 Abott ID now machines.
It seems we have all the time and money in the world to sit on our butts all day but we can’t solve that problem ?

> That should be doable. Give all these places 3 Abott ID now machines.

The machines don't solve the problem. If you have 20 workers, and all are tested every day, you will probably see 2 test positive each day. Then what? Send them home? Test them again? OK, then you have a worker with a positive and negative. Then what? Test again until, what, there are a lot more negatives?

Additionally, just because a worker tests negative doesn't mean they aren't infectious. If you are playing russian roulette with a gun with 100 barrels every day, then eventually you will lose and the outbreak begins again in the nursing home.

the only way to fix this is to live on site as the folks that run electrical plants are doing. You stay on site for two weeks, take some days off, and on return you are quarantined for 3-4 days with frequent testing. AND THEN you can go back to your next two weeks on shift.

Not many people are going to be signing up for this job for $17/hour.

1- Money is not the problem. We’re spending $1T a month sitting on our butt
2- the false positive rate is 0.2%, hardly a problem. Retest if you have to
3- if a worker test negative , yes they’re not infectious at the 99.9% level.
As I said people are dying today in nursing homes from Covid--19. The rate in Europe is ~ 30% to 60% of deaths come from nursing homes, that’s with a general lockdown. We don’t have to be perfect, just better.
There’s no need to complicate this i.e. say, we can’t do it because of a 0.1% problem.

A draft government report projects covid-19 cases will surge to about 200,000 per day by June 1, accompanied by more than 3,000 deaths each day. The White House response: “The President’s phased guidelines to open up America again are a scientific driven approach that the top health and infectious disease experts in the federal government agreed with. The health of the American people remains President Trump’s top priority, and that will continue as we monitor the efforts by states to ease restrictions.” As Trump cheers on lock-down protesters. So what if the projection turns out to be accurate? The White House will blame "the efforts by states to ease restrictions". https://www.washingtonpost.com/health/government-report-predicts-covid-19-cases-will-reach-200000-a-day-by-june-1/2020/05/04/02fe743e-8e27-11ea-a9c0-73b93422d691_story.html

They also provided an interactive tool - you can see how changing the various assumptions and parameters affect their modeled results.

One thing those results make clear - under no circumstances should any policymaker knowingly allow the introduction of an infected person into a population of high-mortality risk individuals such as the elderly, nor should they knowing allow infected caregivers to provide care to high-mortality risk patients.

Limiting lockdowns to the most vulnerable groups is not a new idea, and is it entirely intuitive that these would perform better than a blanket lockdown. But let me take Tyler’s “paternalism” comment a step further. No government action to restrict behavior is ever justifiable without at least posing the question: “Where’s the externality?” Here, the answer is far from clear. People thronging to the beach, say, are doing so consensually. They are presumably aware of the risk/reward trade off, and are doing what they feel is best. The government has in principle some role to play in informing the public of the risks and how to take precautions, but in practice what’s coming from public officials often seems more noise than signal. Plausibly, the young and healthy, whose risks of serious complications are the lowest, will choose the greatest exposure. If anything, the private choice of exposure is arguably below the social optimum given some positive externality of herd immunity. The old and infirm can choose to sequester themselves to avoid exposure; the proposition that they receive a negative externality from the exposure of others doesn’t hold up to scrutiny. The Swedes likely got it right: treat people like the responsible adults they are, issue guidelines but let them act in their own best interests.

The situation will be a little different, I think, when a vaccine is available. In that case, subsidies to encourage vaccination make sense.

The one exception I see to all this is elderly in nursing homes. I’ve seen statistics suggesting that elderly in nursing homes account for half of all COVID-19 deaths. This is shocking and demands major effort at remediation. It should be priority one in this pandemic. THIS is where the negative externality is worst.

Externality=3 weeks in ICU paid for by society (+ exposure risk for healthcare workers). And then the missing ICU beds for everything else that might afflict you. If those going out, and their whole households, sign away their rights to a hospital stay, then this could work. Or we could say, realistically, that we can’t do anything for you at the hospital if you get Covid.

Only if you’re going to cut the young (under 40-50) a check for the astronomical externality going the other way. The benefits of the lockdown are going mostly to those aged 70+, and the costs will be born mostly by the group receiving little (depending on age, minimal) benefits.

If you thought the ok, boomer stuff was bad before Covid, wait till millennials and under find out we sacrificed their livelihoods for the benefit of the oldest among us, oh and yelled at them for being “selfish” for wanting to go to the beach after 40+ days of house arrest, which they willingly put up with for the benefit of others.

It is interesting to note that for a website that so often extols the virtues of market and pricing mechanisms in terms of providing the most efficient means of allocating resources, I am seeing so many autocratic, top-down statist solutions to the current Covid-19 crisis. I observe that people often get seriously wrapped around the axle when they have to come up with solutions that have to apply to everyone in society at large, especially when those solutions require balancing of disparate values; i.e., is it better to save more lives with an extended lock down at the cost of impoverishing vast swaths of society? Well, it beats the hell out of me. What I do know is that it is much easier for me to make this decision for myself. I don't need the nanny state to protect me from myself by forcing me into solitary confinement. The issue of externalities is certainly valid, so groups that are in the care of other agents (i.e., residents of nursing homes, etc.) should probably be protected. It is also legitimate to argue that individuals who are affected by my decision to cavort on the beach with like-minded adults but who also do not wish to share in that risk (i.e., my stay-at-home spouse who might fear me bringing the infection home) should not be forced to share in that risk. That said, these are issues that have traditionally been worked out one way or another inside the family units that are so affected. Do we really get more optimal solutions by having health care authoritarians inserting themselves into these more efficient small-scale negotiations with their own less efficient, obtrusive, one-size-fits-all mandates?

It is somewhat sad to note that in the current atmosphere of fear, nearly all of the libertarians among us appear to have fled for the tall timber.

Dr. Birx: “It’s devastatingly worrisome to me, personally, because if they (the lock-down protesters) go home and infect their grandmother or their grandfather who has a co-morbid condition and they have a serious or a very — or an unfortunate outcome, they will feel guilty for the rest of our lives.” Meanwhile, Trump encourages the lock-down protesters.

My broader point is that dividing the country into groups based on covid morbidity risk will have the ancillary effect of creating liability for those who increase that risk. What duty do we owe those who have high covid morbidity risk? To be clear, I support the efforts of these economists to identify those at high morbidity risk and to promote targeted social restrictions accordingly, because if we don't and let the economy continue to collapse, the future may be too bleak to endure.

Why don’t we poll the at-risk people. I know my grandparents would have found it absurd to put their children’s and grandchildren’s lives on hold, not to mention risk burdening them with incredible future hardship and lost opportunities, just to buy a few more months/years of suffering in a nursing home.

I have a similar concern that those who advocated and imposed overly restrictive lockdown policies based on over-pessimistic modeling *assumptions* and those that advocate undue delays now on lifting such restrictions will feel really guilty for needlessly devastating our economy. I also worry that they will feel guilty for the rest of their lives if their actions lead to such a large backlash that people stop voluntarily distancing and, as a result, provoking such a backlash turns out to cause more infections and deaths.

Unlike the protesters, who can easily avoid infecting their grandparents by not visiting their grandparents in person, those that are imposing unnecessary or backlash-provoking lockdown policies have no ability to alleviate the harm they cause because they insist on imposing the lockdown policies on everyone else.

Dr. Birx has to worry about the health of the nation. Trump has to worry about the health of the nation and the economy and civil rights, and....

Dr. Birx is only one input.

I would go much further than Tyler in questioning the mandatory nature of the proposed lockdowns. And I would ask that others do so as well. I would say that such a proposal -- whatever merit it might have were it voluntary -- is an unmitigated evil when imposed by coercion.

Picture this: You're old; you don't know how long you have to live anyway; and you're being locked into your apartment, perhaps against your will, isolated from friends and family and the great outdoors, for God knows how long, "for your own good." What do you think of them apples?

The key question is: Whose life is this anyway? The individual's or the state's?

Notice that we're not talking here about an argument for protecting the community, because it really is the elderly and others at very high risk that are being discussed. So what is the justification for a mandatory lockdown? Because these "all-star economists" happen to think that *they* should be able to decide what risk-benefit tradeoffs an elderly person should -- must! -- make. Shame on them!

In saying this, I do not mean to globally discredit the risk-differentiating dimension of their approach. It long has been apparent that efforts should preferentially have been directed, from early on, toward protecting the elderly and others at risk. I'm anathematizing specifically the element of coercion, force, and disregard for personal autonomy and choice. And this is not simply disregard; it is disregard plus coercion.

I do not think it wrong to call that not just arrogant, but evil.

I totally agree with the need to stay focussed on the justifications behind governmental intervention, but in this case the rationale is pretty obvious: with a 20% chance of hospitalization, an over-65/70 getting infected has obvious negative externalities on health care saturation.

Health care saturation matters as to whom is left to go out.

But it is who people going out infect that really matters. Why do you get to make choices for others? There are lots of people who have to go out (police, fire, medical workers, utilities, food distribution from beginning to end, etc.) and many others we want to go out (bank workers, government workers, etc.) So many of you think this is an individualized calculation. It is not. You want to go out but you thereby risk the health of many who do not want to be out but are, generally doing the things to make your life and society work.

Its the libertarian fallacy again and again--you are not an island, you are not taking care of everything yourself, you could not get along with no government and no society.

Grow up.

It's the socialist fallacy again and again. Create government funding for a program, in this case health care, then use that to justify yet more government control.

How to respond to this has nothing to do with how we provide health care.

You think you have made some point by mouthing "socialist" but it looks just like mouth breathing to me.

The joy of thinking you're getting into an engaging debate on the internet and get meaningless incoherent replies.

“ What if they ask to be released, in full knowledge of the relevant risks?”

If they die, code them as “Risk-Consented Deaths.” There’s a second-order Straussian element to this. Over time, the number of Risk Consented Deaths will be so much greater than Death Despite Full Isolation that even “gallivanting” old people will want to stay home. Another benefit is that the blame can’t be shifted to the government ex-post. As long as they do their best to protect the elderly in full isolation (such as paying for free delivery, remote healthcare, etc...) and minimize Deaths Despite Full Isolation, they will have done their job. That will in drive better ex-ante decision-making.

I think 0.1% of 20-49 is easier to say than to live.

I mean sure, when we open it will have to be youngest first, but they might not all think that is a good bet. They might not want to be the first penguins in the water.

20 somethings are not generally known for being the most risk averse. Im guessing they'll be very happy penguins to enjoy the summer beaches and bars upon the reopen.

“…we find that semi-targeted policies that simply apply a strict lockdown on the oldest group can achieve the majority of the gains from fully-targeted policies.“

Was this not patently obvious at least a month ago?

It was not obvious to Tyler, who was poo-pooing the idea of segregating at-risk populations as unworkable.

Tyler was strongly rejecting this approach a month ago.

I believe Tyler. Most people didn’t have masks back then, hospitals were overwhelmed, and we were still learning about the virus. Now that we’re over that hump and we can require that everyone wears a mask, we can have a partial lockdown. However, that’s all precluding The Best Approach due to our current political environment.

The best approach would have been to invoke the Defense Production Act on a massive scale to create more PPE (including a thick washable cloth mask for every citizen) and medical supplies. We also needed to limit flights to a greater extent, particularly from Europe, early on. Quarantine policy should not have been left up to the states. Masks and other face coverings should have been mandated from day one, with the former outnumbering the latter over time. The Google/Apple tracing app should have been fast tracked and subsidized. Some degree of surge pricing should have been allowed. Lastly, we should have subsidized deliveries and remote services for the old and vulnerable, and enacted the strictest lockdown for them (no visitors). If all that was done, we would have been able to have more of a partial lockdown a month ago and simultaneously avoided the current death toll. Moreover, all of that, plus significantly more testing, would have been much cheaper than what we’ve spent so far dealing with the economic effects of a full lockdown.

We are so hamstrung by the extremes of either political party that we are blinded to the fact that this is a medical issue above all else. If you approach this issue from a medical first-principles standpoint, the best economic, political, and social policy will follow.

A selective lock down doesn't make a lot of sense. The places we want to close are transmission centers like hospitals, choral rehearsal venues, meat packing plants, public celebrations, Amazon warehouses, schools and old age homes. We're already seeing massive push back against this.

If we focus on vulnerable populations instead of occupational categories, we'll have to lock down old people, men, Hispanics and African Americans. We have social security plans for old people, but we'd need to provide income substitution for the other more vulnerable groups. That just isn't going to happen.

Basically, we don't have the political will to fight this. Trump will do fine selling "One Million Dead" commemorative coins on his web site, but the US has never recovered from Vietnam.

The missing factor is a real understanding of how effective a real lockdown is. Interactions with delivery and service people, medical providers and neighbors all create paths to the outside world. If we look at nursing home data they seem very similar no matter where they are. This is an isolated group of people who have only three paths of infection. First is new residents who may have COVID-19, the second is visits by family and friends, and the third is the nursing home staff. The first and third are most likely to spread the virus through the nursing home, while family visitors are most likely to infect just their loved one. I see this in data from nursing homes in Connecticut where many have 0 or a few infections and many more have infection rates of 10-40% with 25-30% of those causing death. The high rates clearly involve staff perhaps infected by new residents. Nursing home fatalities in Connecticut are 50% of all deaths from coronavirus in a population of only 19,000 people.

Very old people tend to be isolated by choice even if living at home. Their radius of movement and interaction becomes less. However they are increasingly frail and open to severe impact from the virus. Except in contributing to the overall death statistics, I don't think they are big spreaders of the disease. Moderate precautions by those who interact with them might be most effective.

Americans have become rich enough to “opt out” of this particular plague. They seem content to stay home, read books, not pay rent, and wait for this all to blow over.

Perhaps the models should incorporate this.

It seems to have escaped notice that world-wide a selective lockdown of the elderly/vulnerable has taken place. Nursing homes/long-term care facilities/elder care/ call it what you will, have been locked down almost since the beginning of the outbreak. No residents allowed out, no visitors allowed in.

Universally, this plan has failed. Regardless of whether it's been tried in Sweden or Italy or anywhere inbetween. The people under this lockdown form the overwhelming majority of casualties. So why would we think this is a plan that makes sense?

If you want to let 'er rip, then be honest and say so, and be honest that you're sacrificing the elderly, and move on. Don't be disingenous about it.

Let us also be honest that the young will bear the brunt of the myriad burdens created by the lockdown, possibly for decades, while likely receiving very little of the benefit in terms of reduced mortality.

Fair enough. I don't have the answer to what the right approach is, but pretending that it's possible to do selective lockdowns for the elderly, when all the evidence is clear that it isn't, is just disingenuous.

At the same time, thinking that a business-as-usual approach wouldn't have had a significant economic effect as well, is illogical. You can't have a whole swath of people sick (even if mildly), without affecting the ability to do business, and without it causing a significant drop in travel, restaurant visits, etc. Conferences, trade shows, sporting events etc were being canceled around the world way before any governments (China/Italy excepted) mandated lockdowns.

It would be good to have a sensible discussion around what's possible instead of trying to score points and win political dogfights. In the end, we're all in this together. Middle-aged people losing their jobs are way more financially affected than the young, for example. Parents care about their kids' futures. Not to say that the youth aren't heavily affected - it's a pretty terrible situation however you look at it.

I think this assumes that we actually know how to protect the older population. I dont think that is the case. Tracking the nursing homes in our area there are some where I know the place fairly well and those running it. They did everything they could think of, followed all the recommended guidelines and went beyond those and they still had outbreaks. Unless we have reliable testing that can be performed every day we cant be sure that staff or visitors are safe. Even then I suspect we need more than that to make it work.


"optimal semi–targeted or fully-targeted policies reduce mortality from 1.83% to 0.71% (thus, saving 2.7 million lives)"

The massive deficits we are incurring should be funded by a $1 million tax on every individual who considered over a million deaths likely or even plausible.

If they can't afford it- Lyft is hiring drivers in their area.

We could also fund by removing the lockdowns, watching the boomers and silents die off, and taking the social security and Medicaid benifits they would have gotten for the ~0-10 years they had left before Covid and putting it towards paying down the bail-out debt/reimbursing everyone else for what has effectively been a giant gov taking.

Should probably raise taxes on the elderly too. Given how rapidly the virus spreads in group home/multi unit, If we can force enough of them out of their houses and into group homes, we can probably accelerate gains.

On the most lurid Imperial College scenario, population death rate would have been 0.6% (2 million in USA) without "action".

According to recent articles, the average loss would be about 10 QALYs, due to the age skew. That works out to a three week average loss of life expectancy (0.6% of 10 years). Again because of the skew, that would actually be fairly uniform across the age spectrum, except for nursing homes, whose residents have high co-morbidities. That is, the risk increases with age but the QALYs being risked decrease, roughly in proportion.

Now, if I set aside the American Twitter-enhanced penchant for strident puritanical moralizing, then I can't even begin to imagine that a measly 3 weeks - more likely 1.5 - of life expectancy is worth years of lockdown, or even more than a couple of months of it.

After all, house arrest is often considered a punishment. This, as a wild guess, a year of lockdown might be worth 0.6 of a QALY rather than close to 1.0 for a somewhat normal year. Indeed, it seems highly unlikely a vaccine will be available in less than a year. Now the lost 0.4 of a QALY would be about 20 weeks, far exceeding 1.5 or even 3 weeks (to repeat, at any age.)

It seems that our Puritanism has already led us to the point of overpaying in not-so-visible loss of life (QALYs) in order to mollify the noisy Twitterati, and will soon lead us far beyond.

It's no wonder that historically, England wearied of Oliver Cromwell and welcomed the Restoration. I guess something analogous is likely in a year or two. And after all, nothing in the Universe we actually live in guarantees us absolutely zero risk.

“For example, for the same economic cost (24.3% decline in GDP), optimal semi–targeted or fully-targeted policies reduce mortality from 1.83% to 0.71% (thus, saving 2.7 million lives)”

If I’m reading this correctly, a reduction in mortality of 1.12% saves 2.7 MM lives, which means the new improved mortality of 0.71% costs only 1.7 MM lives. Who is projecting that number of deaths?

1. Nursing Homes. Most of them are staffed by people who would struggle to be day-laborers. The system is past broken. The idea the system can be reformed to have reasonable infectious disease mitigation is fantasy.
2. Selective segregation. Aside from the fact that we're already doing that, the phrase "equal protection under the law" is pertinent. 14th Amendment, Sec. 1.
3. Isolation. The idea that spending most or all of your time inside the home is unlikely tenable. I don't think we are, as a species, capable of it. But, hey, it'll be great practice for wannabe Mars colonists!
4. Critical Path Analysis disagree with AT that now is the time to start ground-breaking for vaccine plants. We've got plenty of time before we need worry about that. Months if not years. I find it more than a bit puzzling that with the major acute need in testing and tracing, that vaccine manufacturing is occupying so much editorial space. Perhaps these people are just trolls attempting to distract the vast unwashed.
5. Is the SIR model is sufficiently accurate to be useful for sars-cov-2? Show me the goodness of fit. A bad model can be worse than no model at all.

Tyler slowing pulling his head out of his ass, one blog post at a time.

Presenting Characteristics, Comorbidities, and Outcomes Among 5700 Patients Hospitalized With COVID-19 in the New York City Area

In this case series that included 5700 patients hospitalized with COVID-19 in the New York City area, the most common comorbidities were hypertension (56.6%), obesity (41.7%), and diabetes (33.8%).

Discharged Non-diabetic N=1548
Discharged Diabetic N=533
Died Non-diabetic N=329
Died Diabetic N=224
Readmittedd ~2%


I bet a significant % of “died non-diabetic” were people with other comorbities such as obesity or hypertension (admittedly they were mentioned).

I think obesity is a highly underrated risk factor for COVID-19 relative to age. Why aren’t people talking about it much? Is it taboo? We can save lives if people knew the truth. If I was obese, I would want the government and media to tell me, especially me, to stay home and take no visitors.

In the general population, over 60% of people over 60 years of age have HTN.


"saving 2.7 million lives"

Are they really claiming the virus will double the mortality rate in the USA if the policies are not followed?

Something seems wrong here.

They are helpless idiots who have bought into boomer ideology. They have bought into insidious assumptions cleverly placed by the boomer that all must be sacrificed to further the boomer reign. I’m sure the truth lies somewhere below their estimate but above zero. But let’s not call them “lives” or “people” or “Americans”. They are old people, boomers, and silent gen leaches who continue to collect social security, Medicaid, and low transmission rates from the productive sector.

Gadzooks, the Sweden model. No lockdowns and old people self-isolate.

Dudes, wrecking the economy will not extinguish a virus.

While Sweden had a baby boom, succeeding generations had a similar demographic and cultural make up to the boom gen. The boom gen in Sweden did not seize all economic and political power like the US one, just most.

Neither does opening it. What's your point?

"One question I have is whether the age-specific lockdown in fact collapses into some other policy"

Right. The paper found that throwing away information, like age, leads to sub-optimal policy. One can do better by incorporating age. The broader lesson is to not throw away other information either, e.g., distributed information about individuals' risk preferences, health, lifestyle, work situation, and other information that only such individuals possess. We incorporate that information through a policy of freedom.

Economists to the rescue! Also what common sense suggested over a month ago, but, hey, you got there. Couple things:

1 - What is the cost of a death? Based on life years or constant?
2 - the death rate looks too high?
3 - politicians are frozen. I hope this gives them cover to lead and manage a tough situation. Lockdown isn’t a cure - it slows the death rate.
4 - we have sufficiently scared society into assuming the odds of death are exceptionally high. This will be hard to undo. You have to start some time, I suppose. The anxiety is crazy out there.
5 - Once the common person figures out that the risks of Covid were overestimated by scientists, then they will.... vote for whom? Or, maybe we continue with the “see, death rates are soaring” theme and people stay scared.
6 - the common refrain is that some people live with older people. Therefore, we should ALL lock down. Maybe young people that live with older people stay locked down?

We surely live in interesting times.

A while back I wrote a blog post that gives some practical guidance on how a stratified lockdown might be implemented https://www.fernandomartel.com/post/stratified-social-distancing

The whole freedom thing is a red herring when you consider many of the elderly live in nursing homes where my risk taking spills over to my neighbors at a rate of R0=3, with a 10% chance or more of killing them. You might as well ask for the freedom to shoot a 3 bullet revolver in a crowded market blind folded.

"all-star economists write Covid-19 paper"

Is that a teaser for tomorrow's post on Hassett's cubic model?

lots of people have been sentenced to life imprisonment at the Hague and its predecessors for targeted lockdowns.

you see, "you are under house arrest" and "stay in your ghetto" are the sort of things people say before they are sent to jail for life as war criminals

props for not deleting that, well, at least for an hour or so.

I was serious by the way.

I am directing this, not to Tyler, a good guy, or to Alex, another good guy, but to some of the very bad people out there,
You don't get to say that because you did not know that this was just a one in 20 years bad flu year, you felt confident in your entitlement to use all the forces of the government to force people, regardless of their mental health issues, regardless of their health needs, into fascist/communist lockdown, stuck in their homes with the alternative of being jailed by fascist/communists like yourself, and then say you did not think it was a wartime decision.

Trust me, it was a wartime decision, it was a criminally cruel decision, and some of you were war criminals and many of you were cheering on war criminals. Everybody knows that. You will never read the details of the harm you caused because that is how war criminals roll. But you engaged in evil, and you know it. Don't think you can imagine you thought you were not operating in a war environment. You were, and you harmed innocent people.

"we find that semi-targeted policies that simply apply a strict lockdown on the oldest group can achieve the majority of the gains from fully-targeted policies."

OMG!!!! We would *NEVER* have figure *THAT* out without a model!!!!

Yeah it's pretty clear at this point: don't be old, fat or crowded and get fresh air and sunlight. But those implicate a lot of comfy priors so it's not discussed much.

Also nobody seems to talk much about the fact that absent massive transfer payments, after two months people who don't make a living at a computer are going to leave their houses to go find work.

Either Tyler is being ironic in claiming progress from a paper stating the equivalent of water is wet.

Or he's just as ordinary as the rest.

For the third time: most of the world lives in multi-generation homes. Get that into your head, american economists! It is impossible to do "age-targeting". Urgh!!!

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