7 ms·
I appreciate where you are coming from. (1/2)mv^2 very rapidly becomes unforgiving to the frail human frame due to that annoying square! Many people might loo
by gerdesj 7y ago
I appreciate where you are coming from. (1/2)mv^2 very rapidly becomes unforgiving to the frail human frame due to that annoying square!
Many people might look at 60 -> 70 mph and conclude something like a 16% increase in "danger". However, if we set m = 1 then 60 mph gives 1800 thingies and 70 mph gives us 2450 thingies or 36% "extra danger". I live in metric (with a sprinkle of extra units to taste land) hence: "thingies". I set m = 1 which should avoid problems.
Something as simple as speed is not as intuitive as someone might think. We look at the variable (speed) and it is obviously linear and so we think the implications of increasing it must similarly be linear. But it isn't. The energy in a speeding car is proportional to the square of the velocity of the car. This is a horribly simplistic model but the fundamentals are there.
Now virus propagation ... R is the rate of infection. If R < 1 then infections drop over time. If R > 1 then infections rise exponentially. I gather that R = 3 is the norm for SARS-COV-2 without controls. You can play with a spreadsheet for a simple model to scare yourself.
When the term exponential heaves into view then we should quite rightly shit ourselves and do as we are told. We are far away from worrying about 16:36 which is the result of a one off event but an exponential "thing" over time grows rather fast.
- ryankemper 7y ago> When the term exponential heaves into view then we should quite rightly shit ourselves and do as we are told. And yet we didn't collectively shit ourselves to nearly the same extent for any of the other novel viruses that have popped up in the last couple decades and spread exponentially. Exponential spread is the default state of things. It's only when a virus becomes widespread in a population that the exponential spread ceases, as you indicated in your reference to R. To use a contrived example: Imagine a new virus SARS-CoV-1337 with an R of 250 and an infection fatality rate of .00000001%. Would it warrant the response we've made to SARS-CoV-2? Clearly not. Therefore we need to look at the actual outcomes associated with the virus, and then counterbalance those against the externalities introduced by suppressing spread. Implicitly everyone in favor of lockdown is assuming that the mortality avoided by hunkering down until a theoretical game-changer (vaccine, highly effective antiviral, monoclonal antibodies etc) is available at scale, is a bigger benefit than the negatives incurred by trying to prevent spread (lockdown/containment). My personal opinion is that the externalities of our current approach (I'm speaking from a US-based perspective) far exceed the cost of COVID-19 itself.
- joshuamorton 7y ago> My personal opinion is that the externalities of our current approach (I'm speaking from a US-based perspective) far exceed the cost of COVID-19 itself. How many lives would need to be saved to encourage the current lockdown, in your opinion?
- ryankemper 7y agoLet's back up a bit to talk about the two strategies. (1) Containment lets you indefinitely avoid COVID-19-induced mortality in the short-medium term, at the expense of ongoing, mounting costs to wellbeing and the economy. These costs are certainly non-linear, for example businesses can generally only survive a given number of days/weeks based off their capital expenditure and thus it's not quite as simple as a linear relation. But for our purposes, it's easiest to think of the wellbeing and economic cost as being in direct proportion to how long we spend in containment. The postponement of mortality only becomes the true avoidance of mortality when we get a "game-changer": a vaccine or a highly effective treatment that seriously improves outcomes. Given that we must practice indefinite containment until we develop the "game-changer", we are executing a strategy which is based off a temporally unbounded future event. Therefore the potential drawbacks are unbounded given that the strategy involves waiting for a miraculous leap forward in COVID-19 vaccination or treatment. (2) My proposal is an approach where we try to direct testing resources and governmental assistance to protecting the most at-risk members of society. These groups are encouraged to shelter at home and are supported in doing so. Bans on freedom of movement, transaction, etc are lifted. Non-at-risk individuals are encouraged to return to work. Given that we inflicted psychological harm on millions of individuals, we also would probably want a policy where someone is allowed to not work, but they must formally quit their job in order to be allowed to collect unemployment for up to a year (we likely also need to adjust unemployment because it's just way too high relative to wage earners right now). What we need to avoid is a case where someone "chooses" (in scare quotes because we have done true psychological damage to people) not to work for a year but their company can't let them go, since otherwise the company cannot replace them with a working employee. So in short, we let people do what they want, we strongly encourage the at-risk to shelter at home and put out appropriate public health messaging in proportion to the real risk (which means overall WAY less fearmongering since we're so out of whack currently). The uncertainty benefit is something we should implicitly factor in as well. The ultimate end state of my proposal is much more "known" than with containment (because we have no bound on containment worst-case scenario but we can use Ferguson to get a decent bound for mitigation). We're not sure how much mortality we will see, but with a 0.9% IFR and 82% of the population being infected we get about 2.2 million deaths per Ferguson (https://www.imperial.ac.uk/media/imperial-college/medicine/sph/ide/gida-fellowships/Imperial-College-COVID19-NPI-modelling-16-03-2020.pdf https://www.imperial.ac.uk/media/imperial-college/medicine/s...). I think that's a great upper bound to use. BTW I think once accounting for vector exhaustion (not everyone has the same risk of infection) and what I feel is a more realistic IFR, we'd be closer to 600,000 deaths in the "realistic" scenario IMO. --- The last thing I want to say is that I actually think in terms of wellbeing-years or quality-adjusted-life-years, and not just "lives". My belief is that the life of a healthy 12 year old is several times more valuable than the life of an 80 year old with heart disease, to use an example. So, while it's hard for me to give you a "real" number, I'd say if we could save 20 million wellbeing-years, then lockdown was probably worth it. But keep in mind that means that LOCKDOWN_COVID19_MORTALITY_REDUCTION - LOCKDOWN_EXTERNALITIES >= 20 million wellbeing-years.