Micromort
en.wikipedia.org
en.wikipedia.org
500 milimorts + 500 milimorts = 750 milimorts
Playing russian roulette using a sixshooter loaded with 3 rounds is 50% chance of death. It's 75% if you do another try. "Adding" another try does not translate to "adding" the metric. It just adds confusion.
Setting aside micromorts, you can't say a 50% chance of death + a 50% chance of death = 100% chance of death, either.
But when some unit looks like a meter or gram (especially using the micro- prefix here), it should behave accordingly.
(assuming your aim is good & lethality on hit is 100%)
yet
hating a probability or a unit of measure is like hating a cloud or a tree or a ray of the sun. it just is.
and this attachment this rejection of what is engenders a senseless suffering.
one might respond, measures aren't real. but then, what's the use in hating what is unreal?
on the other hand, the way we are drawn to elegance and beauty can be awakening and motivating in the quest of truth.
Why can't they just use dBuM where 60dBuM=Death?
This would solve your problem as well – just overload a different operator: 500 millimorts || 500 millimorts = 750 millimorts.
Nothing arbitrary about it. But if you don't like putting resistors in parallel, go ahead and put them in a series, and then compute the electrical conductance of the pair:
10 S "+" 10 S = 5 S
> and if you asked me (ie a layman) to "add two resistors together", i sure as hell wouldn't wire them in parallel lol
Maybe that's the reason why people don't ask you to fix their wiring or to design their schematics for them? Parallel impedances are just as ubiquitous and important as serial ones.
First, yes, if you want to figure out your chance of dying from doing two things, you would have to do the math as you describe.
You’re Russian roulette example isn’t a problem with the units. The chance of the bullet firing is not constant in each round, which is why the odds work as you describe. Each round has a different micromort number.
The point of a micromort is to compare activities for risk, not to calculate the total chance of dying after some series of activities. That would be impossible anyway; there are infinite activities you go through, each with their own micromort level.
In fact, 10 micromorts + 10 micromorts is 19.9999 micromorts (you have too many nines). But within the relevant standard of accuracy, 19.9999 = 20.
The same is true for more complicated estimates. For example, 10 micromorts every day for a year is 3643.3 micromorts, which is practically 10 times 365.
It's not completely accurate, but it's certainly good enough for the intended flavor of computation.
Also, as you observed, the system breaks down with large probabilities. I think a good analogy here is Newtonian mechanics. If you drop a ball of a building, and want to know how long it will take to fall, then for all practical purposes you can ignore the effects of relativity. But if you were to throw the ball at half the speed of light, then you would need to be more careful. (In more ways than one...)
So let m be 10^-6 .
Probability of survival of one event = 1 - m ~= e^-m .
Probability of survival of two events = (1 - m)^2 ~= (e^-m)^2 = e^-2m ~= 1 - 2m.
To add micromorts:
double add_micromorts(double x, double y) {
return -1e6 * expm1(
-log1p(x * 1e-6) - log1p(y * 1e-6)
);
}
return x + y - x * y * 1e-6;
But you can add micromorts in the case where n people are playing separate games of Russian Roulette.
As another example, the Wikipedia page says that this is equivalent to 1 micromort:
> Traveling 6000 miles (10,000 km) by jet (cancer due to increased background radiation)
If you're just trying to calculate your own risk as a passenger, you can't just multiply 1 micromort by the number of 10,000 km trips you take. But if you're operating a flight, then you can multiply it by the number of passengers on this 10,000 km flight.
It has more to do with the nature of the thing you're trying to model, than it does with the nature of the unit.
So for example, if working in a coal mine is 10 micromorts per work day, and you choose to do it each day, it seems pretty reasonable to call that 10 * 5 days * 50 work weeks = 2500 micromorts per year. You're "paying" that cost each time you decide to go to work, and if you decide to work next year it won't somehow "cost" less micromorts – the possible yous who died last year won't be around to make the decision.
and from 2015: https://news.ycombinator.com/item?id=10571077
and a day later, the unfortunately unnoticed https://news.ycombinator.com/item?id=10584488.
from NYT: Converting this to micromort language, an individual living in New York City has experienced roughly 50 additional micromorts of risk per day because of Covid-19. That means you were roughly twice as likely to die as you would have been if you were serving in the U.S. armed forces in Afghanistan throughout 2010
Point is that we know Covid has very different risk profiles based on who you are. Saying "That means you were roughly twice as likely to die as you would have been if you were serving in the U.S. armed forces in Afghanistan throughout 2010" probably underestimates your risk if you live in a nursing home, but it vastly, vastly overestimates your risk if you're 20 and in good health.
I don't see that as an issue with the measure.
Moreover, average micromort increase in a population is a useful metric, in the same way GDP is a useful metric, even if your individual productivity is very different.
though i'm actually a big fan of this unit (e.g. as an expression of the relative risks of various activities), it's clear from the comments section that when people are presented with a simple number they tend to treat the underlying reality that it reflects as simple too. this is FAR from the only domain where people reduce complicated things to scalars, and then do atrocious, hideous, unspeakable things to those scalars (take standard deviations, %changes over time, and the like), and then make claims about reality based on the results of those mathematical perversions (i take particular aim at the social sciences here. sorry. they certainly don't have a monopoly on statistical innumeracy, but their domain is just more rife for this sort of abuse).
Micromorts feature a fair amount on Tim Harford's excellent More or Less¹ show. It strikes me that people who like the micromort as a topic would probably find the podcast generally interesting too.
Edit: After following dang's links to previous micromort discussions I see that other people will bring up More or Less in these threads too ;)
Cos: 'Stress results...often... in a kind of enviousness'? (-;
That can be broken down to motorcycle on the freeway (light traffic) vs congested city vs N traffic lights vs curvy mountain roads, riding around sunset, etc.
Knowing how dangerous something is in aggregate is not as useful as the specifics.
Those who are will more likely have a false sense of lower risk than their actions would subject them to. Those who aren't might be scared away by a larger value than they would actually be subject to.
This could even become a self fulfilling prophecy where activities with high average micromorts will only attract people more willing to engage in risky behavior, thus inflating the tail of extreme behavior that causes most of the mortality, increasing the activity's average micromorts over time.
Since everyone starts with the same number of credits, I suppose that's a sort of equity.
There's got to be some more formal line of research or thought about population management in a post-aging world.
But what are the alternatives if people stop dying of old age? If the birth rate is even marginally higher than the very small death rate, we eventually over populate. The only way to resolve that is some kind of culling mechanism. War, starvation, and disease are what usually happens to humanity when resources get too constrained.
But now we have nukes.
I also question whether a mass die off event on this planet won't lock us out from ever rebuilding a spacefaring civilization. We've already used up all the readily accessible fossil fuel that was necessary for us to get this far.
"[] placed a 12-gauge shotgun under his own chin and proceeded to fire the weapon, dying instantly. [] followed, but survived the self-inflicted gunshot wound with a severely disfigured face"
I wonder if there’s some similar measure where we could basically treat everyone as slightly radioactive. Entering an enclosed space would reduce the maximum separation of everyone and increase the minimum possible exposure (and by consequence, everyone’s chance of death).
Since we’d then have a useful quantity to measure and track, we could then do accounting with our risk of death by COVID-19 (i.e. “I’m not going to the store today because I’m over my exposure limit for the week”)
for instance, flying 100 times/year (100 times tiny risk) is hardly riskier than flying once (tiny risk). most people don't even give that risk a second thought.
many common events can double risks (or more).