4 ms·

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 p

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.

mannykannot 1mo ago
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.
- benatkin 1mo ago
  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.
wat10000 1mo ago
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.
- riazrizvi 1mo ago
  Okay step away from the waving hands and read the source material.
  - wat10000 1mo ago
    Could you be a little more specific? https://www.prb.org/news/how-many-people-have-ever-lived-on-earth/ 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?
    - deleted 1mo ago
      [deleted]
    - saalweachter 1mo ago
      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.
      - aswegs8 1mo ago
        Something seems off. This source says: https://www.prb.org/news/how-many-people-have-ever-lived-on-earth/ https://www.prb.org/news/how-many-people-have-ever-lived-on-... before 8000 BCE: ~9.0 billion births, 8% 8000 BCE–1650 CE: ~85.4 billion, 73% after 1650: ~22.6 billion, 19% Looks also different to OPs website
zhoBEENG 1mo ago
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.
- fxd 1mo ago
  In other words, the Flat Birth Theory. We can call them flat birthers
  - karim79 1mo ago
    Come on now. We all know the birth is not flat. It can be clearly seen from space.
  - song_synth 1mo ago
    Off with the Flat Birthers, I'm a Reverse Birther! https://www.youtube.com/watch?v=OsAIhGoKVuo https://www.youtube.com/watch?v=OsAIhGoKVuo
- mmmnnn 1mo ago
  https://www.youtube.com/watch?v=KKpILoUMMb8 https://www.youtube.com/watch?v=KKpILoUMMb8
yummypaint 1mo ago
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.
- magneticnorth 1mo ago
  This is a good point, it's not as far off as it seems from a quick glance.
- throwawayk7h 1mo ago
  They should have scaled the probability curve by the derivative of log(time).
  - aand16 1mo ago
    Why?
- logicallee 1mo ago
  >exadurates this word is usually spelled exaggerate (yes, with two g's.)
  - thaumasiotes 1mo ago
    > 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...
Supermancho 1mo ago
> "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.
WA 1mo ago
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.
- stickfigure 1mo ago
  I picked my own age and location. My life expectancy is apparently 59, my friends average 4.3 children, and 9% of my cohort died as infants. Yeah, not even close. Neat idea, needs real numbers.
Tenoke 1mo ago
Yes, this is exactly what I expected (showing the anthropic principle in action), so I am disappointed they are not sampling correctly.
satvikpendem 1mo ago
That's sort of boring though, we generally know what it's like to live near the modern day already.
- troyvit 1mo ago
  I think it'd be cool to compare a modern day life in rural Ethiopia to what I'm used to.
gradus_ad 1mo ago
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...
- mrtnmcc 1mo ago
  Notice the log scale on the year axis. There is far more probability mass during older years because of that.
  - janalsncm 1mo ago
    Log scale should only affect how the years are displayed on the chart, not how they are sampled.
- wat10000 1mo ago
  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.
  - eks391 1mo ago
    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.
    - wat10000 1mo ago
      You could definitely call it stark, but the comment I replied to suggested that it would be well over 50%.
- janalsncm 1mo ago
deleted 1mo ago
[deleted]
mcv 1mo ago
Yeah, it feels it might be a bit skewed to produce interesting results. My first attempt, despite a life expectancy of 31 and a 34% chance to reach 40, lived a glorious 65 years. Then again, my next two attempts died at 4 months and 4 years. But they were both from before 1000 AD. So maybe it's just the year that's skewed. But the fourth reached 65 and was from before 1000 AD. Only 1 in 4 was from after 1000 AD.

mannykannot 1mo ago

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.

benatkin 1mo ago
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.

wat10000 1mo ago

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.

riazrizvi 1mo ago
Okay step away from the waving hands and read the source material.
- wat10000 1mo ago
  Could you be a little more specific? https://www.prb.org/news/how-many-people-have-ever-lived-on-earth/ 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?
  - deleted 1mo ago
    [deleted]
  - saalweachter 1mo ago
    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.
    - aswegs8 1mo ago
      Something seems off. This source says: https://www.prb.org/news/how-many-people-have-ever-lived-on-earth/ https://www.prb.org/news/how-many-people-have-ever-lived-on-... before 8000 BCE: ~9.0 billion births, 8% 8000 BCE–1650 CE: ~85.4 billion, 73% after 1650: ~22.6 billion, 19% Looks also different to OPs website

zhoBEENG 1mo ago

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.

fxd 1mo ago
In other words, the Flat Birth Theory. We can call them flat birthers
- karim79 1mo ago
  Come on now. We all know the birth is not flat. It can be clearly seen from space.
- song_synth 1mo ago
  Off with the Flat Birthers, I'm a Reverse Birther! https://www.youtube.com/watch?v=OsAIhGoKVuo https://www.youtube.com/watch?v=OsAIhGoKVuo
mmmnnn 1mo ago
https://www.youtube.com/watch?v=KKpILoUMMb8 https://www.youtube.com/watch?v=KKpILoUMMb8

yummypaint 1mo ago

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.

magneticnorth 1mo ago
This is a good point, it's not as far off as it seems from a quick glance.
throwawayk7h 1mo ago
They should have scaled the probability curve by the derivative of log(time).
- aand16 1mo ago
  Why?
logicallee 1mo ago
>exadurates this word is usually spelled exaggerate (yes, with two g's.)
- thaumasiotes 1mo ago
  > 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...

Supermancho 1mo ago

> "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.

WA 1mo ago

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.

stickfigure 1mo ago
I picked my own age and location. My life expectancy is apparently 59, my friends average 4.3 children, and 9% of my cohort died as infants. Yeah, not even close. Neat idea, needs real numbers.

Tenoke 1mo ago

Yes, this is exactly what I expected (showing the anthropic principle in action), so I am disappointed they are not sampling correctly.

satvikpendem 1mo ago

That's sort of boring though, we generally know what it's like to live near the modern day already.

troyvit 1mo ago
I think it'd be cool to compare a modern day life in rural Ethiopia to what I'm used to.

gradus_ad 1mo ago

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...

mrtnmcc 1mo ago
Notice the log scale on the year axis. There is far more probability mass during older years because of that.
- janalsncm 1mo ago
  Log scale should only affect how the years are displayed on the chart, not how they are sampled.
wat10000 1mo ago
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.
- eks391 1mo ago
  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.
  - wat10000 1mo ago
    You could definitely call it stark, but the comment I replied to suggested that it would be well over 50%.
janalsncm 1mo ago

deleted 1mo ago

[deleted]

mcv 1mo ago

Yeah, it feels it might be a bit skewed to produce interesting results. My first attempt, despite a life expectancy of 31 and a 34% chance to reach 40, lived a glorious 65 years. Then again, my next two attempts died at 4 months and 4 years. But they were both from before 1000 AD. So maybe it's just the year that's skewed. But the fourth reached 65 and was from before 1000 AD. Only 1 in 4 was from after 1000 AD.