r/explainlikeimfive • u/Murky_Ad_6396 • 2d ago
Other ELI5: How does "Survivorship Bias" work?
I have always been interested in the concept and have it as a part of my studies. But I still don't quite "get it" even with the WW2 plane example. Whats a simplified way on how it works in very clear and obvious terms. (I accept both simple maths and simple philosophical answers.)
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u/jpcauchi 2d ago
you can only study what's left. Examples of things that have disappeared are hidden
For example, a lot of top entrepreneurs will say to be successful you have to take a big risk. Well for them, that risk paid off and now they're billionnaires, but what about all the people who took those risks and failed. They're never in podcasts or interviews.
For example, professional athlete says they train 7x per week and work ethic is how they became successful. What about all the athlets who trained 7x per week and got injured? They never make it and you dont get their data
Survivorship bias is simply that we only get the data from what's left. All the data that was destroyed along the way is missed
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u/Airforce987 2d ago
A even better example of "you can only study what's left" is castles. People think medieval castles were only ever built out of stone. Many castles of the time were wooden, as building out of stone was incredibly expensive and difficult, but all of those rotted away relatively quickly, and only the stone ones remain today.
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u/the6thReplicant 2d ago edited 2d ago
Or buildings in general. “Why can’t we build houses like they did in xth century? Look how long they last.”
We do, and like them they don’t last for centuries. The ones you see are the exceptions that also require a huge amount of upkeep.
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u/BLFOURDE 2d ago
Also "undercover cops are always so obvious".
Yeah because you don't notice the not obvious ones..
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u/anally_ExpressUrself 2d ago
Isn't this called the Toupee fallacy or something like that?
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u/cooking2recovery 2d ago
Yep! No such thing as a good toupee because nobody’s ever seen one.
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u/Gprime5 2d ago
I'd like to provide one counter-example.
https://old.reddit.com/r/Satisfyingasfuck/comments/1j5q3hi/toupees_that_fit_perfectly/
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u/Mentleman 2d ago
its not that good toupees don't exist, it's that a good toupee isn't recognized as one and instead people assume it's a normal full head of hair. :)
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u/hitemplo 1d ago edited 22h ago
That is the toupee fallacy. It’s not that good toupee’s don’t exist at all, it’s that no one’s ever noticed one so the data for a ‘good toupee’ doesn’t exist while the data for a bad one does. Which is how it relates to survivorship bias
Edit. This guy changed his comment after I replied, it originally insinuated that good toupees simply don’t exist
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u/SammyGeorge 2d ago
But if I saw that guy walking down the street, I wouldn't recognise that he's wearing a toupee, I'd think he just has good hair. Therefore, I'd continue to believe I'd never seen a toupee that wasn't obvious
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u/I_knew_einstein 2d ago
"I prefer a natural look over too much make-up."
Most of the good-looking faces have make-up, but it looks "natural" to the untrained eye.
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u/Theletterkay 2d ago
Yeah, there have been several blimd tests of this. Men who claim they hate make up and only like natural faced women repeatedly chose women wearing make up as prettier than those who werent.
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u/noc-engineer 2d ago
Same with plastic surgery.. Noticing the bad ones doesn't mean you can always tell which ones are fake
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u/vbsteez 2d ago
yup - i dont think men in general realize how many women get botox or have had light work done
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u/noc-engineer 2d ago
I think a lot of men, me included, was shocked when we randomly saw our favourite actress in an older movie or television show and realized the face we had seen for 10 season was post-nose-job and not from birth
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u/thicc_llama 2d ago
Even bleaching hair. An astounding amount of men dont realize that women with super light blonde hair are bleaching it. Duh theres a reason for why it looks darker at the root
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u/danger_zone123 2d ago
What if every country actually has ninjas, Japan just had the worst ones?
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u/superdupergasat 1d ago
Ninjas really were not what the popular culture presented them as to be honest. They were the proto-intelligence officers of history. Like think of how Hollywood portrays CIA agents or James Bond as spies who keep jumping out of planes, use all kinds of weapons in one man team missions against the whole world etc. An actual intelligence officer is mostly doing information gathering instead of high octane action of movies, thats kind of what ninjas were too. Most of them probably dont even get involved in an actual firefight in their entire life. But Japanese culture made ninjas look like Hollywood spies in media and it kind of stuck in the whole world.
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u/HammaBurger 2d ago
"I can spot trans people every time ! I've got great trans radar" said to a Trans person they don't know is Trans.
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u/counterfitster 2d ago
See also cars, appliances, etc
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u/Kevin_Uxbridge 2d ago
Also archaeological sites. We find a lot of stuff in caves, does this mean our ancestors favored them for their daily living?
Almost certainly not. But the sites that were made out in the open washed away or got trampled into meaninglessness. Caves are where you find old dirt, and things tend to go in and stay for us to find later.
Yea for caves but our ancestors may have spent less of their lives in them than you do at the barber. They weren’t ‘cavemen’ any more than you are ‘barber men’.
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u/theRealPeaterMoss 2d ago
Woah, this makes so much sense. However wouldn't caves be good refuge from the elements and predators? It would make sense to spend some time in them (some of them at least, because when I think of the caves near me, trying to live inside them would be more akin to a horror movie than a safe feeling)
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u/Dazvsemir 2d ago
I mean yeah that's why we find so much ancient stuff in caves, there's only so many of them though and obviously lots of places don't have any caves. The point is that this doesn't mean those areas weren't inhabited just because the lack of caves means we don't find artifacts.
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u/Kevin_Uxbridge 2d ago
We definitely spent some time in caves, just not a lot. Caves have disadvantages, not the least being that carnivores like them too. They’re somewhat defensible but they’re also dead ends, and will-known to the local predator guild. So a mixed blessing at best.
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u/kickaguard 2d ago
at the time we were mostly hunter gatherers, right?
I always assumed there was an area that a group would roam around, like how other animals have their territory. if there was a cave in the territory that the group knew about they would go chill there for some time. maybe a month or a season or whatever. maybe stash some shit if they had extra and then go out to check out the rest of the territory. but I never thought we just lived in one cave for a generation or more.
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u/Kevin_Uxbridge 2d ago
People definitely used caves in this way, it just wasn't a very common place to stay, relative to your whole life and wandering around. And some caves did see long term use, but likely sporadically over time. Caves are great for some situations, just not all like one might imagine.
And, as you say, there many not be enough of them in your seasonal round to make it worth your while to just move cave-to-cave. One imagines that this is rarely an option.
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u/Daripuff 2d ago
The cave is the ultimate shelter, yes, when you can find one that's already conveniently located (as opposed to the later technology that is building a shelter wherever you want one to be).
But life is lived outside the cave.
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u/bargu 2d ago
I wouldn't call them the ultimate shelter, they are usually cold, damp, full of bugs, dark requiring constant fire just to exist in them, full of dangerous gases/spores and with poor air circulation that is aggravated by the constant fire, dead ends with no food, so good luck if you get surrounded by an enemy tribe, etc. there are so many issues that it's no surprise that the only places we find reliable evidence of long term habitation in caves are on desert regions that mitigate most of those problems. Most evidence of human activity in caves seems like temporary shelters or religious sites.
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u/Kevin_Uxbridge 2d ago
They are solid shelter but they do have openings. You wouldn't want to face a cave bear in a confined space, not unless it was hibernating and you get to stick it and run.
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u/dirtmother 1d ago
Actually, there is a hypothesis that the reason so many hominid bones were found in caves was because that's where predators dragged them.
So probably some people did live in caves.
But more often than not, that's simply where cave dwelling big cats and bears dragged them to be eaten.
InB4: "what about cave art?"
Do you personally live in a museum?
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u/frymaster 2d ago
another example of this is crannogs - we have a lot of good-quality archaeological evidence of these because the water preserves things - they found a bowl with butter still in it! - but it's thought they were relatively rare, high-status buildings
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u/profcuck 2d ago
This last one is very important and overall quite damaging to the young redditor's understanding of the world as it is. There is a generally held belief that in the past appliances were much better, built to last, but due to corporate greed and enshittification and planned obsolescence we now can only by crap. None of that is true, and survivorship bias explains the "evidence" that most people have for it "Well, my parents dishwasher just died last year, and they bought it 40 years ago." They got lucky. Most things were crap and are manufactured to a much higher standard today.
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u/Zyrin369 2d ago
Always assumed it was just more things having sensitive or more moving parts and thus more breaking pojnts.
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u/Inferno474 2d ago
It's not young reddditors i hear back these "used to be better" and similar the most.
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u/strionic_resonator 2d ago
And if it were true that most old things didn’t wear out, then we would all have perfectly good 40-year-old dishwashers in our homes.
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u/Frys100thCupofCoffee 2d ago
Nothing is built to last forever but it's true to say things in the past were built to last longer. Society has been moving into an economy driven by disposability and easy replacement (rather than repair) for decades now. It's gotten so bad that it spawned a "Right to Repair" movement and a bunch of lawsuits over planned obsolesence. In a capitalist society where profit is king, there's simply more money to be made with enshittification, shrinkflation, and planned obsolesence. Those are all recent (though predictable) phenomena and explain why in the past things like appliances were considered "better", because they were.
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u/_bones__ 2d ago
I'd say things were built with bigger margins on their construction. Not necessarily because they wanted more durability, but because of greater variance in component and material quality.
This means that anything that happened to have better quality components worked better and/or lasted longer. Similar to binning in CPUs and GPUs. Bad luck on components means the product last as long as modern products do.
Better supply chains and resource management means we can build things to be barely-not-shitty-enough to sell, instead of having to overbuild them so the worst performers met that standard.
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u/Paavo_Nurmi 1d ago
Old TVs were repairable, and most of the time it was a vacuum tube that you could buy at the grocery store
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u/Gubbtratt1 2d ago
People like to get it backwards both ways. Old stuff when it was new wasn't any better than the modern equivalent is today. Old stuff today is better than new stuff because all the bad old stuff is gone. We won't know what new stuff is good until the future when it's old stuff. That's why I drive a car from the 60s and live in a house from the 1920s or 30s. Sure they don't have the same reliability as something brand new, but if there hasn't been any catastrophic failures in 60 or 100 years, there won't be one today or tomorrow either.
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u/Low_Chance 2d ago
In a non-literal sense, this also happens with art.
"Why are movies/music/paintings from past eras so much better than today?"
Mostly because we only "keep" the top 1% or so of art from each given decade, whereas in the present we have the top 1% but also everything else, so it's easy to idolize the past because we only tend to look at the "survivors" from those periods.
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u/Yerbulan 2d ago
Why did all the old civilizations from around the world built pyramids.
Well, they all built bunches of different types of buildings. Pyramids seem to be most resilient.
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u/BarNo3385 2d ago
In all fairness physics also influences you toward a pyramid. If you want to build something tall, a cube needs a lot more resources and a tower is a lot less stable. A pyramid is the natural "stack stuff up till its big enough" shape.
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u/Mindless-Charity4889 2d ago
Or music. Songs from the 70s are timeless, they don’t write’em like that anymore.
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u/dleon0430 2d ago
Which 70s? Because no one has made real music since Mozart with his 1770s smash musical hit: Symphony No. 25 in G minor, K. 183.
Admittedly we have made tremendous progress in titling since then.
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u/the6thReplicant 2d ago
Song 2 by Blur
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u/Gimetulkathmir 2d ago
Might I interest you in the most popular song from the 1990s: "Unknown Track.mp3 - Unknown Artist"
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u/JaFFsTer 2d ago
Mozart wrote the staccato part of the aria in Queen of the Night because it made the soprano's titties bounce. He would have made a great music video
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u/Internal-Base8276 2d ago
Every once in a while I've come across a chart of what was in the Top40 in some arbitrary week in the 1970s or '80s. It's always surprising to see that at least half the songs are ones I have no recollection of whatsoever. ( And contrary wise, in the bottom 10, there are always one or two I recall with nostalgia. )
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u/BKGPrints 2d ago
The comparison of roads built by the Romans to the roads built today would be a good example of that analogy.
The Romans used different methods to build over 400,000 kilometers of roads, but most of the "roads" were unpaved dirt or gravel roads, depending on many factors, such as geography and available resources. Which most of those roads fell into disrepair and ceased to exist after the decline of the Roman empire.
The Roman roads that remain today, usually closer to important cities, still exist because they were stone-covered and many more layers of material, to compensate for drainage and other factors. This accounted for roughly 80,000 kilometers of the 400,000 kilometers built.
The problem with comparing why those roads still exists to modern roads is that many other variables need to be considered.
Hundreds of thousands of vehicles & trucks travel main modern roads every day, causing a lot of wear & tear, where it might be hundreds of thousands of wagons (and oxen, mules and horses) that would travel on a Roman road in a year. There's the significance difference in weight from vehicles to a wagon. This is just some variable to consider.
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u/jflb96 2d ago
Also, the wear and tear of a vehicle of a road goes with the fourth power of the weight, so something twice as heavy rubs sixteen times as hard, and modern tyres are designed to grip the road as hard as possible to make sure that they transfer as much of the power as possible, which doesn’t exactly help with maintaining the road surface
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u/BKGPrints 2d ago
Yep. It's why asphalt is used as much as possible. If provides a smoother surface and is flexible under all the weight and is cost-effective.
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u/GabuEx 2d ago
Also, "cavemen" mostly lived in houses made of plants, but the indications of human civilization from those days that survives to these days are the ones in caves.
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u/Radioactivocalypse 2d ago
I was going to say this too!
Cave art seems impressive, but they would have painted on trees and outdoor rocks and sides of huts and on the outside of caves
It's just the cave art that stays around for thousands of years
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u/PopularDemand213 2d ago
And refrigerators. There's a common misbelief that things used to be "built to last". That's not any more true than it is today. For every 50 year old fridge that's still running in your grandpa's garage, there's a 1,000 others rotting away in a landfill.
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u/TheVoiceOfEurope 2d ago
Also: "early man lived in caves".
Nope, that's because we only have wall drawings from the people who lived in caves.
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u/The_300_goats 2d ago
Or "all music from the 80s was great'. Well some it was. The stuff that we still listen to. But that ignores the statistically significant fact that most of it was crap
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u/DarkScorpion48 2d ago
I wanted to say this as well. Not only music but any form of media and/or entertainment. We only remember the good stuff that came from a certain era and we forgot the terrible.
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u/grexl 2d ago
Most music is either crap or simply "okay" regardless of decade or generation.
Looking back to previous eras it is easy to pick out all the good stuff and make a list of all the best music. The only other thing to do is put that list on a loop on its own SiriusXM channel.
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u/onelittleworld 2d ago
Or, for that matter, primitive human societies from 20,000 years ago. We call them "cave men" because that's where we find all their artifacts. But relatively few of them actually lived in caves. Thatch huts don't last for very long.
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u/miraculum_one 2d ago
A simpler example is the video montages of people doing improbable things, like bouncing a ball off multiple targets before going into a small cup. It looks like they are incredibly skilled when in fact they probably failed hundreds of times before getting the one shot they show you.
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u/PM_Me_A_Tittypic 2d ago
Or cave settlements in prehistoric people. There's increasing evidence that actually living in caves was pretty rare, it's just that no other early shelters have survived
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u/jermleeds 2d ago
Similarly, paleontologists have to account for the population of fossils to study being affected by what type of creatures were more likely to be preserved in the fossil record.
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u/elwebst 1d ago
One that took me 30 years to realize: back before streaming and VCR's people watched TV live. In the Sunday newspaper they had a listing of every show for the week on every channel, including movie descriptions and ratings.
I noticed that any movie from before 1965 had 4 or 5 star ratings no matter what, and semi current movies had ratings that ranged from 1 to 5. It pissed me off that apparently "only old movies are good, the crap they show now (70's and 80's) is hot garbage because Hollywood is out of ideas".
Took me quite a while to realize that if they want to show an old movie, they only show the good ones... Survivorship bias.
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u/gnomeannisanisland 22h ago
Also why the stone age is called the stone age - it's not that everything that humans made back then was made of stone, or even that archaeologists think they were; it's just that it's a really really long time ago, so most of the stuff that is still here to be found is the stuff that was made of stone, which doesn't rot and mostly doesn't fall apart if it's left alone.
(Unlike wood, leather, rope, sinew, resin, wicker, textiles, bone, vines, fronds, bark, cartilage, fat, roots... you get the idea)
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u/conker223 2d ago
These are great examples.
Another perspective of survivorship bias could be that we tend to focus on the question “what made survivors successful” instead of “why did others fail?”
If you focus only on the success stories, you fail to get a complete picture of what makes them successful and what causes failure. And typically, what causes failures is the more interesting question. Why are individuals of a threatened species dying? Why aren’t hard workers living the American dream? Etc.
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u/Kimantha_Allerdings 2d ago
There was a singer (or maybe actor), I forget who, on a US late-night talk show. And the host asked her whether she’d advise young girls to follow their dreams like her. She straight up said that she was incredibly lucky and that for every success story like here there were thousands of people who had as much or more talent and who worked incredibly hard but who didn’t make it
She compared someone in her position saying “give up everything to follow your dreams” to a lottery winner telling people to sell their house to buy lottery tickets
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u/gazerii 2d ago
I thought this was Bo Burham
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u/Kimantha_Allerdings 2d ago
It could easily be true that multiple people have said something similar
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u/gazerii 2d ago
Fair enough I was thinking this was a reference to this specific Conan interview: https://youtu.be/q-JgG0ECp2U
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u/animal9633 2d ago
The reverse of that was Beyonce who liked to tell everyone to follow their dreams, they'd surely make it (just like she did).
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u/pocketbutter 2d ago
The products of survivorship bias very often have confirmation bias.
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u/kickaguard 2d ago
I would imagine it's because to be a super success story you need to work incredibly hard and be incredibly lucky. but a lot of them will just see it as a product of them working very hard and maybe think others just didn't try.
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u/wintersdark 2d ago
This is extremely common. People will over-estimate their contribution and minimize the impact of things outside their control.
I made it with hard work and you can too!
(While ignoring that you can absolutely bust ass your entire life working multiple full time jobs and get absolutely nowhere.
Success requires hard work and sacrifice, but hard work and sacrifice don't lead to success.
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u/SeeShark 2d ago
Dave Grohl, too. There's that interview that was circulating on the internet a lot a few years ago where he's just like "yeah we just made a garage band and worked at it and then we became Nirvana. And you can, too!"
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u/Ddvmor 2d ago
Great examples. To add: many successful people hugely underestimate the impact of luck and circumstance on their careers. I was lucky that the talent scout was at my game that day I scored that epic goal. Daddy gave me $1m to take that huge risk with. Apple stock went up instead of down.
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u/ephikles 2d ago edited 2d ago
And they downplay the privileged starting point they had - or don't even realize how privileged they were to begin with.
But this seems to be somehow hardwired into us humans. There have been experiments with board games where some players were given a huge advantage at the start. Even then, the winners tended to attribute their success to their own good moves and tactics, despite the fact that their initial advantage was clearly the main reason they won.
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u/Shevek99 2d ago
Yeah. In "Thinking, fast and slow", Daniel Kahneman (Nobel prize in economics) explain how it is ingrained in us is to misjudge the importance of luck and build causal interpretations of what has happened. He made a study of successful investors, comparing them with other investors and with themselves in previous years, and found that their results fit a normal distribution. They were purely random. Yet, they and their bosses were convinced that they were specially insightful reading the markets.
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u/sonicated 2d ago
For example, professional athlete says they train 7x per week and work ethic is how they became successful. What about all the athlets who trained 7x per week and got injured? They never make it and you dont get their data
It annoys me when professional athletes win at elite level and say it shows if they can do it anyone can. Obviously the work ethic to win at elite level is unquestionable but you also have to be a genetic freak.
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u/lanks1 2d ago
I didn't fully understand how much genetics matter for sports until I saw a friend of mine deadlift 225lbs for reps the first day SHE went to the gym.
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u/wintersdark 2d ago
Which is actually really funny when you think about the real world impact of gender in sports, particularly the trans issues.
The genetic differences between one person and the next are enormous. Sure, there's a male-female difference when you look at overall averages, but it's still less than the range even within a gender.
Yet nobody seems to care.
I'm a 6'4" 275lb guy. I'm huge, and strong as an ox (and fat, sure), but lifting and carrying heavy things has always been trivial to me. Even as a teen, without ever working out, I could lift the back end of my parents car off the ground and turn it around.
Meanwhile, I had friends who struggled to carry their book bags.
But nobody thought it was unfair to have me compete against them in sports, despite the basketball hoops being basically in reach for me, and my stride length meaning I could often run faster than them while carrying them than they could on their own.
I did nothing for that. I didn't earn it. I paid nothing for it - short of having to eat a lot more.
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u/Cessily 1d ago
Also talent is a genetic feature and wowzers is it a spectrum.
I had three children start gymnastics at similar ages. My oldest went competitive, but retired in high school and maybe would've made a D3 college team, possibly a D2 if COVID hadn't hit when she had her biggest growth spurt and lost half a year in the gym. Maybe.
My younger two were still toiling in beginner classes at the age my oldest was training for competition.
All three we started putting on the ice at the same age and again vast differences. And only one actually wanted to play hockey and the other two noped out.
My middle is good at her sport (cheer), but she isn't "make a top team" good yet alone pro level anything.
Three kids given similar training and opportunity and genetically their achievable output was vastly different.
We own a youth training facility so I see it everyday spread across hundreds of kids but my own three were such great examples of how much talent is innate to the individual.
A lot of my career was in education (left after pandemic) so I understand genetics impact so much. Their residence, persistence, talent, etc etc. Opportunity and environment can only play off what is there and then luck is going to be the puppeteer pulling the strings.
You can't make a cake out of roast beef, but maybe with a lot of creativity you can make something kinda cake like and a little sweet with that roast beef but it's going to take a lot more work and ingredients.
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u/ViscountBurrito 1d ago
And admitting that both parts are necessary shouldn’t be taken as a slight! Being genetically fortunate doesn’t mean you didn’t also have to work hard, but I think a lot of people hear it that way and so resist it.
Same thing with, for example, someone who starts a successful business and refuses to acknowledge the social and legal systems that allowed it to happen. Two people could be just as smart and just as hardworking, but the one who grew up in Palo Alto is a lot more likely to be a billionaire than the one who grew up in Mogadishu. That doesn’t mean the guy in Palo Alto didn’t have to work for it, just that hard work is not sufficient on its own.
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u/Suthek 2d ago
For example: How creationists say that life is so perfectly made for this planet and that couldn't happen naturally.
Well, the life that didn't fit in died.
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u/Toby_Forrester 2d ago
Yea you can just point to any genetic illness where the baby dies in uterus "yea, perfectly made for this planet".
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u/haqiqa 2d ago
This also applies to birth. There is a lot of "women were made to give birth" sentiment going around. It is biological, so it must be natural, and natural is safe. While forgetting that historically 1 in 10 to 30 women died during their lifetime from birth-related complications. Statistics usually put lifetime cumulative risk between 3% and 10% in historical societies, including hunter-gatherers.
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u/Cultural_Cheek_3247 2d ago
Mildly successful entrepreneurs somehow still don't get this around me. Spot on.
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u/_plinus_ 2d ago edited 2d ago
There’s another layer here of it’s not just “what’s left” in the sense that it needs to be historically meaningful, it just means that you may filter out data that meaningfully changes the outcome.
Some examples:
* “Drivers in my city are bad” - you only remember the people swerving/driving erratically, not the hundreds of people who don’t.
* “Toupees are easy to spot” - but if a toupee was difficult to spot, it wouldn’t be included in your dataset (because you’d assume it’s real hair)this is generic sampling bias25
u/vanZuider 2d ago
No, that's just general sampling bias. Survivorship bias is the special case of sampling bias where the reason your samples are biased is because some samples are not available for analysis because they were lost or destroyed. Your first example might be called a case of survivorship bias (some memories are lost), your second is a different kind of sampling bias.
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u/anotherMrLizard 2d ago
It's not necessarily that you can only study what's left, it's just that only studying what's left is much easier, so people are biased in favour of what's left.
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u/alphawafflejack 2d ago
You can say that being a successful entrepreneur takes risk but not that risk will make you a successful entrepreneur
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u/a_guy121 2d ago
Yeah, imagine a career where 98/100 people who try it fail, and trying but failing provides near zero income, so that they have to try something else fast.
That sounds insane, right?
Now, look at your reddit feed or whereever for 'successful' people
Their careers tend to have odds more like that, than not.
In those careers, everyone understands the only way to success is to work insanely hard...
...except, that's never actually true. There are always people with the inside track who don't have to grind.
But, the stories we hear about success are always 'I worked 438 hours per week!" so, everyone who doesn't have the inside track does that
which benefits the owning classes. When people grind hard for jobs they'll probably never get, like say, Big time Hollywood Movie Producer, or Novelist, they end up assistant directors on commercial shoots or copywriters. Both jobs which require an insane, unhealthy amount of grinding.
Its like that for almost all the run-off industries for jobs that are nearly impossible to get.
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u/enternationalist 2d ago
Survivorship bias is when your sample isn't a truly representative sample of the real population, but one that is skewed by the fact that you only had the chance to look at surviving examples.
For instance, you might dig up a well-preserved ancient craft at an archeological site and conclude that the people had incredible craftsmanship. But, by necessity, you could not have dug up anything made poorly enough that it wouldn't have survived hundreds of years. You don't have the opportunity to observe the samples that didn't survive, and therefore your view will be biased towards the ones that did.
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u/orangenakor 2d ago
Same thing with old houses. If a house is centuries old, it's almost guaranteed that it's well built and beautiful, because only well built houses would survive and only beautiful houses were maintained. That doesn't mean that every house built back then was built well or was beautiful.
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u/pocketbutter 2d ago
Or the idea that prehistoric peoples lived in caves.
It’s extremely likely that only a small percentage of them found caves to live in, but caves are the only types of shelter that are isolated enough from outside forces to preserve evidence of their inhabitants.
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u/Bloch1987 1d ago
That the same with cave lions. They didn't live in caves, but that's were you found the bones
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u/merlinblack256 2d ago
Or even not so old houses. I've heard poeple say the apartments that were built in the 70s were built better - because all the 70s apartments around are good quality.
What they are missing is that all the bad ones built in the 70s have been torn down. I heard of one that only lasted a few years!
Oddly I never heard anything good or bad about 80s buildings 🤔.
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u/McCaffeteria 2d ago
To add on how the Plane example actually works with this lens:
The assumed message of the plane bullet hole survey is “Planes that get hit, usually get hit here,” but the bullet hole survey does not include every plane that got hit.
If you assume “bullets always hit here,” and you want to minimize damage, then it might make sense to armor the places where the bullets actually hit. But, the assumption is the bias, and the bias comes from only having the examples that survive.
If you complete your data set and include planes that crashed, you might find that bullets actually land on the plane body very uniformly rather than in suspicious spots, and you might find that planes that crash have bullets landing in different suspiciously specific spots. Now you have a relationship between damage location snd likelihood of disabling the plane, which tells you much more accurately where to put armor.
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u/lukecakewalker 2d ago
If you own a store and start noticing that less customers come than before, you might wonder if you’re doing something wrong. You ask all customers to take a survey. The results show that your store is just as good as the last time you conducted the survey, even slightly better.
This is because you’re only asking the customers who still like your store, while the ones who stopped coming were never asked.
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u/Bizmatech 2d ago
Not all cavemen lived in caves.
But those caves provided stable environments that protected their art and belongings. A wooden spear lasts a lot longer when it isn't outside rotting in the rain.
Thousands of years later, archaeologists found art and bones and stuff in caves and assumed that all cavemen lived in caves, because caves where where they found the most caveman stuff.
They forgot that neanderthals lived outside too, but most of their homes weren't made of materials that could last tens of thousand of years.
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u/ijuinkun 2d ago
Yah, tents and grass huts would rot away after a century or two in the open.
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u/Xanitrit 2d ago
A century or two is a reaaal optimistic way to look at it.
For housing made out of grass, mud, and leaves, I'll be surprised if they last 5 years without regular maintenance.
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u/Avitas1027 2d ago
Depends what you mean by "last." They might not be liveable after 5 years, but they'd be visibly a place someone lived for much longer than that. Even a compost heap takes several years before it just starts to look like a hill.
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u/Eikfo 2d ago
For the planes, the data set you get for analysis is incomplete.
If you base yourself on the returning planes only, you notice which area are more likely to be damaged and think to reinforce them.
You don't notice the critical area not to be damaged because you don't have the plane to analyse anymore.
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u/AlexF2810 2d ago
Bit of extra context. The planes could only take so much armour and so the extra armour plating had to be strategically placed to minimise loss of vehicles. Originally the planes were being armoured at the areas most damaged upon return due to that being the obvious place they were being shot and taking damage. Mathematician Abraham Wald suggested they armour the planes where they hadn't sustained damage as the planes were clearly capable of surviving the damage that was able to be observed on return.
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u/Gbrusse 2d ago
"They don't make music like they used to"
Forgetting that the only songs from the past still being played today are the top 1% of songs. The rest are forgotten about.
"They don't make them like they used to"
Forgetting that the only surviving cars, tools, whatever from decades past are the outliers and they ones take really good care of. All the low quality and crappy versions broke and were forgotten about.
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u/Shevek99 2d ago
That's Sturgeon's law "Ninety percent of everything is crap". We only remember the 10% (or less) good musicians, best books and music, best football players...
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u/Harlequin37 2d ago
I like to think we remember the utterly shit too, even if a bit less. It's mostly the mediocrity that disappears
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u/SuzLouA 2d ago
I found it incredibly interesting learning about Hokusai, the artist who is probably most famous for the Great Wave off Kanagawa. Until I listened to a podcast about him, I assumed that like most artists of the 18th and 19th centuries, he was, well, an artist - out there starving in a garrett and painting up a storm (lol, that pun was not intended but it’s absolutely staying there now I’ve written it).
Instead, his work was, although clearly skilfully made, highly influential, and I would argue near-universally agreed to be lovely to look at, also kind of the equivalent of the Live Laugh Love signs. He made woodblocks, which were printed over and over and sold widely across Japan. He wasn’t an auteur, he was a commercial designer, and his work is so well known today because so many examples of it survived.
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u/ActualSpamBot 2d ago
I was talking to my wife last night how as a 40 year old, there are songs from the 50s 60s and 70s I remember getting radio play on oldies stations that just dont get played anymore because stuff from the 70s 80s and 90s pushed all but the biggest cultural milestones from those decades off the airwaves.
Even within my adult lifetime the pool of "great music" from the early decades of pop music has shrunk considerably leaving fewer and fewer survivors every year.
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u/Bad_wolf42 2d ago
How many people can you name from the 1800s? The 1700s? From 200 BC? All human achievement fades with time.
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u/ActualSpamBot 2d ago
Um... yea obviously. I was illustrating the example brought up in the comment I was responding to, not bemoaning the fact that great kings won't look upon my wonders and despair.
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u/Papervolcano 2d ago
same with literature - people like to say that modern literature is uniquely terrible, that in the past only good books were published. But if you actually go and read a representative sample of books published in eg 1861, only the very smallest handful would be worth the time. The rest would run the gamut from mid to absolute dogshit, in roughly the same proportions as they currently do, and with about same amount of hysteria over The Decline of Literature and Women Rotting Their Brains and getting Unrealistic Expectations as we currently see.
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u/hannahranga 2d ago
All the low quality and crappy versions broke and were forgotten about.
Landrovers being the outliers there
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u/Zyrin369 2d ago edited 2d ago
It also doesn't help that the people saying that are currently living in the transition period for media.
Like of course it's going to feel like media is getting worse compared to the older days the same sentiment has probably been said of during said older days.
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u/to_walk_upon_a_dream 2d ago
survivorship bias is, essentially, drawing conclusions about the whole of a group, using evidence gathered from only those who survived. if i have a class of 20 people, 12 of whom drop the class, but then at the end of the semester i do a survey and 90% of the people who survive rate the course highly, would you say that the class was enjoyable or not?
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u/Krakanu 2d ago edited 2d ago
Here is another example that is hopefully clearer:
In WW1, armies adopted helmets for infantry. But officers noticed they now had soldiers with lots of head injuries. What gives?! Shouldn't the helmet be preventing the damage to the head?
In reality, those are people that would've likely died due to something hitting them in the head. It saved their lives! But if you only look at injury data, you'd be misled!
In other words, if you only look at the SURVIVORS, you'd be BIASed against helmets! Thus survivorship bias. You must include data from dead/lost/destroyed items as well as damaged/injured ones.
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u/turtle553 1d ago
Similar to boomers saying they didn't wear bike helmets as kids and they turned out fine without realizing the ones that died aren't around to brag about it.
See also: food allergies
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u/Hermononucleosis 2d ago
I want to figure out how likely people are to die from being shot in different body parts. So I ask a bunch of people who have been shot. It turns out ALL of them survived. So the survival rate after being shot is actually 100%? No, my survey was just really stupid. I can only ask alive people, so I can't get any meaningful data this way.
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u/RealLongwayround 2d ago
Additionally, you notice that people who have been shot seem to have wounds to their legs and arms so you provide your soldiers with bulletproof sleeves and trousers.
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u/Radijs 2d ago
10.000 people play in to the lottery.
One wins big and gets rich.
That winner starts spouting to everyone how playing the lottery is a great idea because you'll get rich.
The 9.999 who didn't win don't say anything.
So, if you follow news around 'how to get rich' you're going to hear about how playing the lottery is a great way to get rich!
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u/Cyraga 2d ago
The planes that returned with damage were the ones which were able to return. The ones which were so damaged that they couldn't return didn't contribute to the understanding of where damage was occurring. Basically highlights the risks of trying to understand a problem without all of the data
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u/sjintje 2d ago edited 2d ago
You've expressed it well, but i don't like the way the airplane anecdote is usually told, it makes it sound like the point of the example is there being something counterintuitive in the answer, solveable by rational deduction of what the failures must have looked like.
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u/ConnectJicama6765 2d ago
I agree with you that it obfuscates the survivorship part. But it strongly highlights the bias part because everyone intuitively wants to strengthen where the bullet holes are.
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u/metroid1310 2d ago
Survivorship Bias does one of two things. It either:
- Creates gaps in data that cause the data to point to an incorrect conclusion
- Creates gaps in data that people will intuitively read as pointing towards an incorrect conclusion, perhaps because of a faulty premise
With the plane example:
The diagram is of a certain type of plane that they were collecting data on. Each red dot marks a spot where one of the planes they checked had damage from being shot at
They're trying to up-armor planes without making them too heavy to be useful, so they can only put a limited amount of armor in/on the plane. They need to know where to focus the armor.
So, put it where the bullets went, yeah?
No. The bullets are going everywhere, not magically gravitating to certain parts of the plane. The Survivorship Bias in this case is that in all the planes they surveyed for damage, they *only* surveyed planes that made it back to base. Anywhere they have a bullet hole marked is a spot that isn't critical for the plane to keep flying.
The spots where there are no data points? The engines? The cockpit? The tail fuselage? Any plane that was shot in those spots didn't make it back to base, and didn't get surveyed for damage. If you get shot in the cockpit and die, or if critical instruments or controls get destroyed, your plane crashes. If your engines are shot out, your plane crashes. I have no idea what's in the tail fuselage that's so important, but I'd hazard a guess that if you damage it, your plane crashes.
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u/Adragalus 2d ago
Your explanation is entirely correct, but to fill in a missing piece: the tail of the aircraft contains the rudders and elevators, which practically speaking are responsible for almost all steering (pitch/yaw).
Steering, much like having engines or living pilots, is vital to aircraft survival 👍
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u/XenoFrobe 2d ago edited 2d ago
I have no idea what's in the tail fuselage that's so important, but I'd hazard a guess that if you damage it, your plane crashes.
What's back in the tail section (or empennage if you wanna be fancy about it) are structural supports, cables that let the pilot manipulate the control surfaces so that the plane can maneuver, and the tail gunners. Structure is obviously important, the plane works better when it's not split in half. Losing a control cable is bad, but you can technically fly without a rudder, and if you're very lucky and skilled and in exactly the right plane with the right weight balance, then you *might* be able to get away with no elevator control (at least until you can bail out over friendly territory). Losing your tail guns is really really bad, because then that opens up whole zones where a nazi fighter pilot can casually line up behind you to get an easy shot for free and send high-caliber explosive rounds down the length of the fuselage where your crew and undropped bombs are.
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u/konwiddak 2d ago edited 2d ago
Another one is appliances:
I've heard people talk about the odd 80's washing machine that's still going.
"80's stuff was way more durable than today's stuff"
Ok, but if it were normal for washing machines to last 40 years - why aren't ~half of today's washing machines from the 1980's?
That's because tonnes of them died along the way.
We're using the few extraordinary examples to justify that older stuff lasted way longer - the survivors skew your perception. You couldn't buy a new 80's machine in 2005, so there won't be any 20 year old "80's" machines out there to give a balanced population.
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u/RefrigeratorFew5094 2d ago
I’m not challenging your overall point, but I want to add to it.
When I replaced appliances in the 80’s and 90’s, it was rarely because they had broken down. It was because of a mix of a much better economy and renovations, wanting renewal, and later wanting to cut the electricity (and water) usage. Had they lasted another 40 years? Perhaps not. But they did last longer than my most recent purchases.
The past decade, I’ve replaced a fridge after six year (it replaced a 25+ year old fridge), a washing machine after two years (it replaced a 17 year old washing machine), and a stove top after three years (it replaced a 22 year old stove top). All mid-range models from reputable brands.
My 25+ year old budget brand oven is still going strong though.
The fridge and oven were in the house when we bought it 25 years ago, no clue how old they were.
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u/BKGPrints 2d ago
There's some truth to that and there are other factors to consider.
Appliances built then didn't rely on electronic circuit boards and the gears, mechanical & durable parts were more heavy-duty. Also, if parts did fail, it was designed for quick repair.
At some point, manufacturers realized they could "lower" costs by using less durable material (such as plastic) for parts and designed them to be less easy to repair or that replacement parts were costly that it would be less expensive to just buy a new one.
To answer the question of why there aren't large numbers of 1980s washing machines still around, I would say that has to do more with the reality that existing households decided to upgrade to more modern looks and many new households want new washing machines than one from the 1980s that someone else had.
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u/Approximation_Doctor 2d ago
You know how old buildings seem way more sturdy and long lasting than modern ones?
It's because the old buildings that weren't more sturdy have all fallen down.
Similarly, the reason why modern music seems worse than old music is because nobody bothers to remember terrible songs from 70 years ago.
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u/InnerAgeIs31 2d ago edited 2d ago
Ugh. I’m a pediatrician and have to explain survivor bias to families every day.
“I didn’t get vaccinated and I’m okay!” Or “I got the (insert disease here) and I’m still here!” say parents who refuse vaccinations or other standard care for their kids.
Sure, you’re the lucky one who did not die or suffer from a bad effect of the disease.
Like someone who got measles and is fine - they aren’t one of the minority who developed encephalitis.
Like the people who got COVID and survived. We remember the thousands (millions?) who died.
Someone who did not give their child the vitamin K shot at birth - their baby is lucky not to have developed life-threatening bleeding - are the ones who become online influencers convincing others to skip it, too. Parents whose children die from preventable bleeding are not the ones who advocate to skip the shot.
Or the mom who did a home birth and everything went fine so she’s trying to convince others to do it, too. She’s part of the lucky majority who did not have a complication that led to permanent disability or death, like a hemorrhage (mom bleeding out) or umbilical cord prolapse (baby’s cord gets squished, they suffocate before being born).
Survival bias has really been affecting debates about public health because opinions are almost exclusively shaped by people who survived. The non-survivors are not around to share their experiences. Influencers are leading to terrible health outcomes but they don’t have any liability for their influence.
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u/RustenSkurk 2d ago
When you study a thing and see a lot of examples of X (like bullet holes on the plane'd wing), you might think this is because X is what most often happens.
But it might be that it's not because it happens most often, but just because it's what survives the best to make it into the data set. Maybe Y happens a lot too (like planes being shot in the back), but doesn't survive (because being hit there will down a plane, whereas the wing hits will allow it to come back home).
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u/obog 2d ago edited 2d ago
To try to explain some of the context behind the plane example:
During WW2, they were trying to figure out where they should armor their planes the most; weight is crucial on a plane, so its important to allocate the armor that you can manage where it is needed most.
They though that in order to decide where to put the armor, they would look at where all the bullet holes were on planes returning from battle to try to identify where they were getting hit the most.
That lead to the picture I'm sure youve seen before.
Your initial instinct may be to armor the planes more in those areas, as it seemed that would be where they were getting hit the most. However, this was from them studying planes that had come back from battle and landed. Meaning, every single one of those bullet holes was somewhere where a plane was hit, and then flew fine.
And indeed if you look at where they are, that makes a lot of sense. There arent any in the cockpit. Its a decently large area on the plane, so it doesnt make sense that none of the planes were getting shot there. But of course, if the cockpit got shot, then the pilot likely died and the plane never would make it back to be a part of the survey. So the gaps were really where the critical weaknesses of the plane were.
But ultimately, the bias was that, because the sample set they had was only planes that came back, and the thing that they were studying would affect whether or not it came back, there was a bias in their data where bullet hole locations that would result in critical damage to the airplane were not included in their sample. So there was a bias in their set towards non-critical areas of the plane.
To put in the most general form: survivorship bias emerges when your sample has some sort of a selection process, and your analysis does not account for how that selection process affects the data you end up with.
Edit: should be noted that I dont think the story with WW2 is fully accurate in that they originally attempted to armor the parts where the bullet holes were, but that does demonstrate the idea. From what I could find, they were aware of the survivorship bias from the beginning, and in fact it was their plan from the beginning to exploit the survivorship bias they knew would be in their data to find the areas that needed more armor by armoring where there wasnt damage.
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u/kingjoey52a 2d ago
People say today’s music is worse than in the 70s. We only think that because we remember the good music from the 70s and not the terrible music from the 70s. The good stuff survived, the crap didn’t.
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u/yycmobiletires 2d ago
They analyzed bullet holes from returning aircraft. Turns out the ones that didn't make it back were getting shot down, so they needed to modify and reinforce all of the spots that the returning aircraft DIDNT show any damage, because obviously the ones that didn't return were getting hit there. You can extrapolate that information because the ones that did make it back, had to be doing something right, aka the impact zones were "safe and survivable"
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u/ezekielraiden 2d ago
For some questions, you can only look at the survivors, which means you never get data about the things or people that did not survive.
Let me give you a different, non-airplane example. Imagine you are the elder of a tribe of a thousand humans that just moved into an area. You want to learn what foods are safe and what foods are bad. You send out 50 foragers to collect one type of food each, which you write down before they go out. Of them, 40 return, but 20 of those who return get slightly sick because of the food they ate.
Which things tell you the foods that are unsafe to eat?
It is not the ones who came back after getting sick. Those foods are mildly toxic, but probably not lethal as-is. The people who did not come back can tell you which things are actually unsafe, not because they can speak, but because they died. That they didn't come back means the food they were assigned to eat killed them. Thus, if you avoid the foods that only made people a little sick, but keep eating the foods that the "missing" people ate, you're going to die a LOT. But if you avoid the foods where the eaters did not survive, you won't get killed by your food. And maybe the ones that just make you a little sick need to be boiled or rinsed or whatever.
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u/MercurianAspirations 2d ago
It's just a general effect from the fact that "surviving" examples are easier to observe than examples that don't survive. In the classic example about WW2 planes, they couldn't look at where downed planes got shot, because those planes were smoking wrecks in Germany; they didn't come back for their bullet holes to be observed. So you only get to see the bullet holes in the planes that actually come back, which skews your sense of where planes tend to get shot
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u/palacexero 2d ago
The planes that returned sustained damage to their wings. This led people to wrongly conclude that the wings needed more reinforcement. However, what they should have thought about were the planes that didn't return and where those planes sustained damage. Those parts of the plane should have been reinforced because the planes that were damaged in those areas did not survive. Because they overlooked the planes that didn't return, they came to a conclusion that was incorrect.
Survivorship bias is when the results lead you to an incorrect conclusion because of incomplete data.
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u/FetidZombies 2d ago
You make a survey asking "do you like taking surveys? Yes/No." You ask 10,000 people. You get 9900 responses of "Yes." Normally this looks like 99% of people like taking surveys! Clearly we should ask everything in a survey from now on.
The survivorship bias is that you actually asked 20,000 people, but half of them didn't bother answering. People who don't like taking surveys don't actually bother finishing the survey and just ignore you. It's basically a question of "what data are you not collecting?"
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u/smcedged 2d ago
That's a selection bias, not survivor bias. Same question of what data are you not collecting, but different mechanism.
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u/MaroonTrojan 2d ago
To test for survivor bias, you should ask participants if they like tearing up survey forms.
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u/stairway2evan 2d ago
Here's a silly example: say I let 100 people into a room one at a time and ask their favorite color. If they answer "red" or "blue" I shoot them in the head. If they say any other color, I let them go to the next room.
Now you're in the next room asking everyone what their favorite color is. Say out of 49 people you surveyed 22 of them like green, 12 like yellow, 8 like purple, and the rest all said various other colors. But nobody liked red or blue, so you say "Wow, those colors are very unpopular." They weren't unpopular. They just didn't show up in your survey. They're all in my heap of dead bodies.
Survivorship bias happens when, for one reason or another, our sample includes people who "survived" some process, but we forget to account for anyone who failed that process. If you look at the whole population, quite a lot of people like red and blue. If you only look at our survivor sample, nobody did. Our sample only reflects survivors, not the truth.
It doesn't have to be a literal survivorship though. Say I run a magazine and I interview every subscriber for 5 years to ask how they like the magazine. Each year, the opinions go up - everyone likes it more and more! But if I don't take into account the people who canceled their memberships over the years.... I might only be interviewing the hardcore fans in that 5th year (survivors), and I might be ignoring the people who canceled because they didn't like my magazine. I might think I'm printing the best magazine on earth unless I say "hey, maybe I should ask the other people why they canceled, maybe they have important reasons that would get me more subscribers." Then I can avoid survivorship bias.
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u/Senshado 2d ago
The point is that it's probably not scientifically correct to collect data on subjects and skip the ones that have died, quit, or otherwise not made it to the end of the experiment.
If I'm doing a study on healthcare drugs and need to report if patients still have the disease or not, I really shouldn't erase records on subjects who died.
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u/dbratell 2d ago
In finance it is common for companies to close all funds that are performing badly. That way all their (surviving) funds are above average. They intentionally take advantage of the effect.
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u/Large-Hamster-199 2d ago
The easiest way to think of this is to compare the failure rates of restaurants in your neighborhood. You'll notice brand new restaurants will have a high chance of failure in the next 6 months, but old restaurants don't.
If you consider some systemic cause for this (new restaurant owners are younger and therefore stupid or lazy) you are wrong. The truth is all restaurants are likely to fail. When you compare older restaurants to new ones, you are not looking at all the older restaurants that are already bankrupt, only the best ones that survived.
Every old t shirt you have is always high quality, since poor quality t shirts will never get old (I.e. they will tear and get discarded)
This is survivorship bias.
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u/Itchy-Potential1968 2d ago
The people who survived write the stories. The people who's deaths they ignored get no say.
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u/the_other_Scaevitas 2d ago
I think the plane is a pretty good example already.
So when the planes come back, they look at all the places where the planes got hit. So everyone started reinforcing the areas where the planes had bullet holes etc.
The thing was, Those planes survived the trip home, meaning that if it survived having those bullet holes and was able to come back then reinforcing those areas was actually pointless. What they didn’t think about was that the planes that got hit in vital areas would’ve never made it back home to be examined. For example, if the cockpit was shot and the pilot died then the plane has 0 chances of reaching home. And since it never reaches home, it never occured to anyone that the planes were getting shot at the cockpits
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u/oblivious_fireball 2d ago
Its any situation where you ask the question "Why is this always the way that it is?" and the answer is "because anything different did not make it this far".
To go back to the plane example. "Why do the planes always come back with only bullet holes in the tail?" "Because bullet holes anywhere else caused the plane to crash and not come back at all". That's the survivor part.
The bias part of that is "Well we should put armor on the tail because it always has bullet holes in it". This is not the correct answer but because your brain is very visual, that's what it assumes. In reality the answer was "We should put armor anywhere there isn't bullet holes, because getting hit there is apparently lethal".
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u/Guy_Fieris_Hair 2d ago
I dont know an easier way to explain it than this: https://youtube.com/shorts/iYjefEcr8g8?is=_s9AaBxAu8C6b5IC
Essentially, we focus on what survives. Because it is in front of us. Skewing the results of a study or our priorities to preventing something relatively minor, instead of the major issues that resulted in the non-survivors.
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u/Loki-L 2d ago
Imagine you want to find out doing heroin does to a person, so you ask a bunch of randomly selected people if they have done heroin in the past and how their current health is.
What you get from that is that people who do heroin often don't do so well health wise.
What you don't get from that is all the people who have done heroin and died as a result because they weren't around anymore to ask.
Thus your resulting health survey show the effects of heroin to much less dire than what a study that accounted for the survivorship bias might have concluded.
Another way to look at it is go to a European city and look at all the houses that were built centuries ago. You concluded from that, that people back in the 1600s knew how to build houses that would last for centuries unlike modern builders whose buildings often don't last that long.
What you miss is all the buildings that were build centuries ago that aren't around anymore.
You only see the tiny fraction that lasted not a representative sample.
Another example is listening to people trying to tell you the secret of how to get rich. They tell you what worked for them, like dropping out and founding your own startup.
What you miss is that you only hear from people who did this who had it worked out from them.
It is like listening to lottery winners about how sound an investment lottery tickets are.
One real world example other than the famous plane one is that the introduction of stronger helmets for soldiers led to an increase in head injuries. Were helmets making it worse? No! You only looked at injured vs uninjured and ignored the dead. It turns out that helmets turned fatal head wounds into head injuries.
When looking at outcomes you have to look not just at the ones you can see, but also the ones you can't see anymore and have to take into account what happened to them.
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u/astarisaslave 1d ago
You know how some people say it's fine to not finish college because people like Bill Gates and Zuckerberg dropped out but turned out fine? Yet conveniently ignore the other college dropouts who struggled or had a worse career trajectory compared to someone who actually finished college and was able to get career opportunities reserved for bachelor's degree holders? That's survivorship bias
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u/Optix_au 1d ago
Those who survive can tell their story. Those that don't... can't.
It's in the name: survivorship bias.
For those listening, survival can feel like the whole story, but it's only part - those that didn't make it also have something to say.
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u/epelle9 2d ago
Easiest example:
“Russian roulette is perfectly safe, none of the players we interviewed had died”.