This is neat, but I don't think it's actually drawing the year from the correct probability distribution - "a random birth is far more likely to fall near the present" is correct, but in 5 "random" choices, only one was from anywhere near modern day.
I did a statistical analysis and you are correct. The issue seems to be that crude birth rates from around 500CE and earlier are overestimated significantly. The bad source seems to be Kaneda & Haub, "How Many People Have Ever Lived on Earth?", where they assume a flat crude birth rate of 80 for all BCE dates. The probability distribution is just a function of pop and CBR, so it results in significantly decreasing modern birth probabilities.
In other words, the Flat Birth Theory.
We can call them flat birthers
Off with the Flat Birthers, I'm a Reverse Birther!
https://www.youtube.com/watch?v=OsAIhGoKVuo
Come on now. We all know the birth is not flat. It can be clearly seen from space.
https://www.youtube.com/watch?v=KKpILoUMMb8
There are more statistical issues. I drew a person from 1984, living in Germany and recalculated their life several times. In almost all cases, their mother died while they were in their thirties, often both parents. This is simply far from reality.
[dead]
I think it's working as intended. The year is simply a randomly chosen year not related to the density of births in that year. It would be a boring tool if it actually chose "random year based on random birth" because almost every choice would be from 1900 onward...
That’s not what it says on the tin though. “Drawn at random from everyone who has ever lived” means years will not be uniformly distributed.
This is a case where I think they should change the wording as opposed to the functionality. I like that it's a random year regardless of population density.
But as other have noted it's almost certainly not just a random year.
I do think the cleanest and most fascinating interpretation is what the title says "One life, drawn at random from all who have ever lived" which clearly is about random people and has nothing to do with the year.
But I think experientially, the preferred feeling for a user is a random deep dive into the circumstantiality of different eras and different geographies than our own, rather than a true-to-life re-rolling that would constantly turn up 20th and 21st century outcomes. So the spirit of it is probably closer to the random year idea, but it's literally not random year, but maybe randomly something else, like eras however designated.
If the implementation was correct it wouldn’t be hard to let the user choose either option.
Yes, many births would be within the last 200 years but it’s still very different to be a man born in the year 1950 in New York vs a woman in 1950 in rural China.
That would certainly be easier at this point, but I like the “random human life” idea more.
I’ve reflected in the past about how lucky I am to have been born where I was, when I was, and be given the abilities that I have. Sure there are plenty of people that were luckier, but also a lot who were less lucky, most of whom are dead.
Should we call this a cargo cult
"random" != "uniformly random", if you want to be pedantic.
But "is far more likely to fall near the present" = "is far more likely to fall near the present". The author makes the claim about probability distribution themselves, then does the opposite.
You're right, yet I agree with the website's approach. The goal of this site is to educate users about how people lived, not educate them about stats. IMO. I would have chosen the same algo.
It's clear to me that an even bigger HC crowd would howl "Oh, how boring, look at him choosing pretty much only still alive people" if he had done the 'uniformly random" selection. C'mon!
Notice the log scale on the year axis. There is far more probability mass during older years because of that.
Log scale should only affect how the years are displayed on the chart, not how they are sampled.
The site covers a 300,000 year span, so a randomly chosen year would average ~150,000 BCE, which definitely isn't happening.
The skew towards the present isn't as stark as that. World population has exploded in the past couple of centuries, but it hasn't been high for very long. 1900 to present only covers ~11% of all births.
1900 to 2026 is 127 years (inclusive), so 0.04% of the year range available, yet it only has 11% of all births. That's certainly a skew, although I suppose subjective whether or not that's stark. At a >3x order of magnitude, it's certainly significant though.
You could definitely call it stark, but the comment I replied to suggested that it would be well over 50%.
> "a random birth is far more likely to fall near the present" is correct,
If the selection is from the population at random (as the UI indicates), but it specifically says it's based on a random year (during which humans were present) first as a filter. It's much more likely to select far from the population explosion.
The x-axis being log scale by default visually exadurates the effect if you are thinking about it in terms of area under the curve. This confused me also.
>exadurates
this word is usually spelled exaggerate (yes, with two g's.)
> yes, with two g's
The reason there are two Gs is that the first one is assimilated from a D. The etymological structure of the word is ex-ad-gero,¹ "from-toward-carry".
This happens for everything. Compare accelerate [ad-celero] / accommodate [ad-con-modus] / impossible [in-pot-s-ibilis] / intelligent [inter-leg-ents].
(Note that a doubled consonant in Latin is pronounced differently from a single one, as is still true today in Italian. English draws no distinction, which makes the etymological spellings likely to confuse English speakers.)
¹ This was already the form of the word in Latin. It looks malformed to me; I can't explain why exaggero is a first conjugation verb (with passive participle exaggerata) rather than simply being a prefixed form of its root (ag)gero, in which case the participle would have been exaggesta. Gero and aggero are both third conjugation verbs...
They should have scaled the probability curve by the derivative of log(time).
Why?
This is a good point, it's not as far off as it seems from a quick glance.
I guess you are right, but it makes it more interesting if the picks are not almost all from the recent past. On the other hand, I would also guess that spreading the picks evenly across the time range might result in many being from times with little data to differentiate them.
It makes the premise of the entire site flawed, though. And it defeats the purpose of the convenient button provided to redraw a year. That is what should allow you to find a pick that might be more interesting, rather than messing up the randomness promised by the site and the HN title.
That's sort of boring though, we generally know what it's like to live near the modern day already.
I think it'd be cool to compare a modern day life in rural Ethiopia to what I'm used to.
Yes, this is exactly what I expected (showing the anthropic principle in action), so I am disappointed they are not sampling correctly.
How near is near? With ~100 billion people having ever lived, the odds of a randomly selected life falling within the past couple of centuries are not all that high.
Okay step away from the waving hands and read the source material.
Could you be a little more specific? https://www.prb.org/news/how-many-people-have-ever-lived-on-... puts the halfway point at over 2,000 years ago, so you'd expect less than 50% probability of getting a random year that's not BCE. "A random birth is far more likely to fall near the present" is true in relative terms; the timeline on the web site goes back 300,000 years and you're very likely to get something in the past few thousand years, which is pretty near to the present when compared to a third of a million years. The random years it gives me fit into that pretty well, so I guessed that the person I replied to might be using a narrower definition of "anywhere near modern day" than that. Hence why I asked. If I missed something, could you kindly point out what I missed, instead of whatever this is?
The stat I keep in my back pocket is that you can roughly divide the total time lived by humans (the integral of population over time) into three tranches, with one third of human experience being before the dawn of agriculture, and one third being after 1600. (Related fun fact: WWII was about 1% of human experience, based on the back of the envelope that ~50% of the world experienced "being at war" for nearly a decade.)
The distribution of human lives versus years lived by humans will skew earlier, because infant mortality was absurd for the first two tranches, with something like 50% of people dying before the age of five, so it will be more like 40-40-20 over those time periods.