Cute theoretical argument for #flattenthecurve at any point in the distribution
What is #flattenthecurve?
The primary theory behind #flattenthecurve is assuming that everybody who will get COVID-19 will eventually get it anyway...is there anything else you can do?
It turns out it’s very valuable to
Delay the spread so that a) the peak of the epidemic spread is lower (#flattenthecurve)
Also to give public health professionals, healthcare systems, etc more time to respond (see diagram below)
A tertiary benefit is that ~unconstrained disease incidence (until it gets to herd immunity levels) is not guaranteed, with enough time to respond, aggressive public health measures (like done in Wuhan, Japan, South Korea etc) can arrest the disease at well below herd immunity levels
Why should you implement #flattenthecurve
If you haven’t been living under a rock, you’ll know that COVID-19 is a big deal
We have nowhere near the number of respirators, ICU beds, etc, for the peak of uncontrolled transmission (Wuhan ran out of ICU beds, and they literally built a dozen hospitals in a week, a feat Western governments may have trouble doing)
When should you implement #flattenthecurve policies?
A lot of people are waiting for specific “fire alarms” (eg, public health authorities sounding the bell, the WHO calling it a pandemic, X cases in a city) before they start taking measures.
I think this is wrong.
The core (cute) theoretical argument I have is that if you think #flattenthecurve is at all worth doing at any time, as long as you’re confident you are on the growth side of the exponential growth curve, slowing the doubling time from X days (say) to 2X days is good for #flattenthecurve and public health perspective no matter where you are on the curve.
Wait, what?
Okay, let’s consider a few stricter versions of the problem
Exponential growth guaranteed + all of society
One way to imagine this is if #society all implemented your policy (because of some Kantian or timeless decision theory sense, say)
Suppose you are only willing to take measures for Y weeks, and for whatever reason the measures are only strong enough to slow down the virus’s spread rather than reverse the curve.
if the doubling rate is previously 3 days and everybody doing this can push it down to 8 days (or push it up to 2 days), then it’s roughly equally good (bad) no matter when on the curve you do those measures.
Exponential growth NOT guaranteed + all of society
Next, relax the assumption of exponential growth being guaranteed and assume that measures are strong enough to reverse the curve of exponential growth (as happened in China, South Korea, Japan)
I think you get the same effect where the cost of X weeks of your measures should be the same no matter where you are on the curve, plus now you got rid of the disease (with the added benefit that if you initiate your measures early, less people die/get sick directly and it’s easier to track new cases)
A downside is that a successful containment strategy means you get less moral credit/people will accuse you of fearmongering, etc.
NOT all of society
Of course, as a private actor you can’t affect all of society. Realistically (if you push hard), your actions will be correlated with only a small percentage of society. So relax the assumption that everybody does it, and assume only a few % of people will do the same actions as you.
But I think for #flattenthecurve purposes, the same arguments still roughly hold.
Now you’re just (eg) slowing the growth rate from 3 days to 3.05 days instead of 3 days to 8 days.
But the costs are ~ linear to the number of people who implement #flattenthecurve policies, and the benefits are still invariant to timing.
Practical considerations
How do we know that we are on the growth side of the exponential/S curve?
Testing seems to lag actual cases a lot.
My claim is that approximately if your city has at least one confirmed or strongly suspected case of community transmission, you’re almost certainly on the exponential trajectory
Aren’t most other people’s actions different depending on where you are on the curve?
Sure, so maybe some mitigation actions are more effective depending on other people’s actions (eg, refusing to do handshakes may be more effective when not everybody has hand sanitizer than when everybody regularly uses hand sanitizer, for example)
I think the general argument is still the same however
Over the course of an epidemic, wouldn’t the different actions result in different R0 and doubling times, so you’re you’re then doing distancing or whatever from a different base?
Okay, I think this is the best theoretical argument against the clean exponential curve stuff.
I still think it’s not obvious that you should do more #flattenthecurve policies later on, if anything this pushes you to doing it earlier
Conclusion
If you think #flattenthecurve is worthwhile to do at all (which I did not argue for much here, but is extensively argued elsewhere), it’s at least as good to do it now as it is to do it later, and plausibly better to do soon rather than later.
Updated version on https://docs.google.com/document/d/1BDm_fcxzmdwuGK4NQw0L3fzYLGGJH19ksUZrRloOzt8/edit?usp=sharing
Cute theoretical argument for #flattenthecurve at any point in the distribution
What is #flattenthecurve?
The primary theory behind #flattenthecurve is assuming that everybody who will get COVID-19 will eventually get it anyway...is there anything else you can do?
It turns out it’s very valuable to
Delay the spread so that a) the peak of the epidemic spread is lower (#flattenthecurve)
Also to give public health professionals, healthcare systems, etc more time to respond (see diagram below)
A tertiary benefit is that ~unconstrained disease incidence (until it gets to herd immunity levels) is not guaranteed, with enough time to respond, aggressive public health measures (like done in Wuhan, Japan, South Korea etc) can arrest the disease at well below herd immunity levels
Why should you implement #flattenthecurve
If you haven’t been living under a rock, you’ll know that COVID-19 is a big deal
We have nowhere near the number of respirators, ICU beds, etc, for the peak of uncontrolled transmission (Wuhan ran out of ICU beds, and they literally built a dozen hospitals in a week, a feat Western governments may have trouble doing)
https://www.flattenthecurve.com/ has more detailed arguments
What are good #flattenthecurve policies?
The standard stuff like being extremely aggressive about sanitation and social distancing
https://www.flattenthecurve.com/ has more details
When should you implement #flattenthecurve policies?
A lot of people are waiting for specific “fire alarms” (eg, public health authorities sounding the bell, the WHO calling it a pandemic, X cases in a city) before they start taking measures.
I think this is wrong.
The core (cute) theoretical argument I have is that if you think #flattenthecurve is at all worth doing at any time, as long as you’re confident you are on the growth side of the exponential growth curve, slowing the doubling time from X days (say) to 2X days is good for #flattenthecurve and public health perspective no matter where you are on the curve.
Wait, what?
Okay, let’s consider a few stricter versions of the problem
Exponential growth guaranteed + all of society
One way to imagine this is if #society all implemented your policy (because of some Kantian or timeless decision theory sense, say)
Suppose you are only willing to take measures for Y weeks, and for whatever reason the measures are only strong enough to slow down the virus’s spread rather than reverse the curve.
if the doubling rate is previously 3 days and everybody doing this can push it down to 8 days (or push it up to 2 days), then it’s roughly equally good (bad) no matter when on the curve you do those measures.
Exponential growth NOT guaranteed + all of society
Next, relax the assumption of exponential growth being guaranteed and assume that measures are strong enough to reverse the curve of exponential growth (as happened in China, South Korea, Japan)
I think you get the same effect where the cost of X weeks of your measures should be the same no matter where you are on the curve, plus now you got rid of the disease (with the added benefit that if you initiate your measures early, less people die/get sick directly and it’s easier to track new cases)
A downside is that a successful containment strategy means you get less moral credit/people will accuse you of fearmongering, etc.
NOT all of society
Of course, as a private actor you can’t affect all of society. Realistically (if you push hard), your actions will be correlated with only a small percentage of society. So relax the assumption that everybody does it, and assume only a few % of people will do the same actions as you.
But I think for #flattenthecurve purposes, the same arguments still roughly hold.
Now you’re just (eg) slowing the growth rate from 3 days to 3.05 days instead of 3 days to 8 days.
But the costs are ~ linear to the number of people who implement #flattenthecurve policies, and the benefits are still invariant to timing.
Practical considerations
How do we know that we are on the growth side of the exponential/S curve?
Testing seems to lag actual cases a lot.
My claim is that approximately if your city has at least one confirmed or strongly suspected case of community transmission, you’re almost certainly on the exponential trajectory
Aren’t most other people’s actions different depending on where you are on the curve?
Sure, so maybe some mitigation actions are more effective depending on other people’s actions (eg, refusing to do handshakes may be more effective when not everybody has hand sanitizer than when everybody regularly uses hand sanitizer, for example)
I think the general argument is still the same however
Over the course of an epidemic, wouldn’t the different actions result in different R0 and doubling times, so you’re you’re then doing distancing or whatever from a different base?
Okay, I think this is the best theoretical argument against the clean exponential curve stuff.
I still think it’s not obvious that you should do more #flattenthecurve policies later on, if anything this pushes you to doing it earlier
Conclusion
If you think #flattenthecurve is worthwhile to do at all (which I did not argue for much here, but is extensively argued elsewhere), it’s at least as good to do it now as it is to do it later, and plausibly better to do soon rather than later.