Survivorship bias is the logical error of concentrating on survivors (successes) and ignoring casualties (failures).
When we do so, we miss the true "base rates" of survival (the actual probability of success) and arrive at flawed conclusions.
Survivorship Bias 101
History is written by the victors. But if we exclusively focus on these successes, we allow survivorship bias to distort our understanding of the world.
But what is "survivorship bias" and how does it work?
Here's Survivorship Bias 101!
👇👇👇
Survivorship bias is the logical error of concentrating on survivors (successes) and ignoring casualties (failures).
When we do so, we miss the true "base rates" of survival (the actual probability of success) and arrive at flawed conclusions.
Put simply, exclusively focusing on successes may actually inhibit our ability to identify (and replicate) the actions that led to such success.
An atheist named Diagoras is shown portraits of people who prayed and were saved from death at sea as proof of God's existence.
Diagoras replies, "I see those who were saved, but where are those painted who were shipwrecked?"
Survivorship bias can lead to a deeply-flawed understanding of cause-and-effect relationships.
Let's look at some examples.
The U.S. wanted to add reinforcement armor to specific areas of its planes.
Analysts plotted the bullet holes and damage on returning bombers, deciding the tail, body, and wings needed reinforcement.
By only plotting data on the planes that returned, they were systematically missing data on a critical, informative subset - the planes that were damaged and unable to return.
The "unseen" planes had sustained damage that was not.
Wald concluded that armor should be added to the unharmed regions of the survivors.
Where the survivors were unharmed is where the planes were most vulnerable.
Wald had identified the survivorship bias and avoided its wrath.
Where else do we see survivorship bias arise?
We all love business success stories. We love to read about companies and people who have achieved incredible success and fame.
We scan their backgrounds in desperate search of the actions or features that led to that success.
But these conclusions are flawed.
For every company that pursued a moonshot idea and is now worth billions, there may be 10 who did the same and collapsed.
Analysts may try to calculate the performance of funds or groups of stocks using only the survivors at the end of the period.
By ignoring closed funds or stocks removed from an index, we bias the data and overstate returns.
Flawed data ➡️ Flawed decisions
To actively fight this, we must study the features of both successes and failures.
The "seen" and the "unseen" are equally important in guiding our decisions.
So the next time you read a story of the hero who won, be sure to reflect on all of the heroes who lost, whose stories are not told.
Special thanks to @austin_rief of @MorningBrew, whose interesting tweet on new founders sparked this thread. https://t.co/ldSVsPP4uX
1/ New founders spend too much time trying to emulate mature companies they admire, and not enough time learning what those companies did in the early days.
— Austin Rief \u2615\ufe0f (@austin_rief) December 5, 2020
Understanding the journey is more important than knowing where they are today.
Fooled by Randomness by @nntaleb: https://t.co/fB9ncIMlvE
Great blog from @ShaneAParrish and @FarnamStreet: https://t.co/o1T85OJMl7
1/ An Allegory of Finance
— Sahil Bloom (@SahilBloom) July 18, 2020
I have been posting a lot of educational (and humorous!) threads on finance, money, and economics.
My mission is simple: to demystify these concepts and make them accessible to everyone.
All of the threads can be found below. Enjoy and please share!
More from Sahil Bloom
Shared a lot of wins publicly in 2021, so it feels appropriate to share the losses just as publicly.
Here are my 10 biggest Ls from 2021 (and what I learned from each one):
Dopamine Addiction
Humans were not made for social media—the dopamine hits are dangerous.
I fell victim.
On several occasions, I found myself constantly refreshing my notifications on a viral thread.
It was gross.
I’m learning to physically force separation to avoid it.
Hustle Culture Fail
I spent the better part of the last decade as a hustle culture aficionado.
Then I burned myself out and was totally incapable of thinking creatively.
I made a change. Now I:
• Work like a lion
• Sleep 8 hours
• Take more walks
My life & work have 10Xed.
Solana Fail
I invested in Solana early and was riding high when it hit $30+ in April—10X+ on my investment.
I sold it and thought I was the next Warren Buffett.
Then it hit $100, $200, & $250—as I stubbornly sat on the sidelines refusing to re-enter.
I am not Warren Buffett.
The Hedonic Treadmill
I tweeted this in May—and then failed to practice what I preached.
Every win felt a bit less exciting. It’s part of our biology, but it was no way to live.
Measure internally, not externally.
Here are my 10 biggest Ls from 2021 (and what I learned from each one):
Dopamine Addiction
Humans were not made for social media—the dopamine hits are dangerous.
I fell victim.
On several occasions, I found myself constantly refreshing my notifications on a viral thread.
It was gross.
I’m learning to physically force separation to avoid it.
Hustle Culture Fail
I spent the better part of the last decade as a hustle culture aficionado.
Then I burned myself out and was totally incapable of thinking creatively.
I made a change. Now I:
• Work like a lion
• Sleep 8 hours
• Take more walks
My life & work have 10Xed.
Solana Fail
I invested in Solana early and was riding high when it hit $30+ in April—10X+ on my investment.
I sold it and thought I was the next Warren Buffett.
Then it hit $100, $200, & $250—as I stubbornly sat on the sidelines refusing to re-enter.
I am not Warren Buffett.
The Hedonic Treadmill
I tweeted this in May—and then failed to practice what I preached.
Every win felt a bit less exciting. It’s part of our biology, but it was no way to live.
Measure internally, not externally.
The Hedonic Treadmill is real.
— Sahil Bloom (@SahilBloom) May 21, 2021
Humans have a tendency to quickly return to a baseline level of happiness after positive events.
Step off the treadmill.
Focus on increasing your happiness baseline, not on the height or frequency of the spikes above it.
More from For later read
Wow, Morgan McSweeney again, Rachel Riley, SFFN, Center for Countering Digital Hate, Imran Ahmed, JLM, BoD, Angela Eagle, Tracy-Ann Oberman, Lisa Nandy, Steve Reed, Jon Cruddas, Trevor Chinn, Martin Taylor, Lord Ian Austin and Mark Lewis. #LabourLeaks #StarmerOut 24 tweet🧵
Morgan McSweeney, Keir Starmer’s chief of staff, launched the organisation that now runs SFFN.
The CEO Imran Ahmed worked closely with a number of Labour figures involved in the campaign to remove Jeremy as leader.
Rachel Riley is listed as patron. https://t.co/nGY5QrwBD0
SFFN claims that it has been “a project of the Center For Countering Digital Hate” since 4 May 2020. The relationship between the two organisations, however, appears to date back far longer. And crucially, CCDH is linked to a number of figures on the Labour right. #LabourLeaks
Center for Countering Digital Hate registered at Companies House on 19 Oct 2018, the organisation’s only director was Morgan McSweeney – Labour leader Keir Starmer’s chief of staff. McSweeney was also the campaign manager for Liz Kendall’s leadership bid. #LabourLeaks #StarmerOut
Sir Keir - along with his chief of staff, Morgan McSweeney - held his first meeting with the Jewish Labour Movement (JLM). Deliberately used the “anti-Semitism” crisis as a pretext to vilify and then expel a leading pro-Corbyn activist in Brighton and Hove
Morgan McSweeney, Keir Starmer’s chief of staff, launched the organisation that now runs SFFN.
The CEO Imran Ahmed worked closely with a number of Labour figures involved in the campaign to remove Jeremy as leader.
Rachel Riley is listed as patron. https://t.co/nGY5QrwBD0
SFFN claims that it has been “a project of the Center For Countering Digital Hate” since 4 May 2020. The relationship between the two organisations, however, appears to date back far longer. And crucially, CCDH is linked to a number of figures on the Labour right. #LabourLeaks
Center for Countering Digital Hate registered at Companies House on 19 Oct 2018, the organisation’s only director was Morgan McSweeney – Labour leader Keir Starmer’s chief of staff. McSweeney was also the campaign manager for Liz Kendall’s leadership bid. #LabourLeaks #StarmerOut
Sir Keir - along with his chief of staff, Morgan McSweeney - held his first meeting with the Jewish Labour Movement (JLM). Deliberately used the “anti-Semitism” crisis as a pretext to vilify and then expel a leading pro-Corbyn activist in Brighton and Hove
There is some valuable analysis in this report, but on the defense front this report is deeply flawed. There are other sections of value in report but, candidly, I don't think it helps us think through critical question of Taiwan defense issues in clear & well-grounded way. 1/
Normally as it might seem churlish to be so critical, but @cfr is so high-profile & the co-authors so distinguished I think it’s key to be clear. If not, people - including in Beijing - could get the wrong idea & this report could do real harm if influential on defense issues. 2/
BLUF: The defense discussion in this report does not engage at the depth needed to add to this critical debate. Accordingly conclusions in report are ill-founded - & in key parts harmful/misleading, esp that US shldnt be prepared defend Taiwan directly (alongside own efforts). 3/
The root of the problem is that report doesn't engage w the real debate on TWN defense issues or, frankly, the facts as knowable in public. Perhaps the most direct proof of this: The citations. There is nothing in the citations to @DeptofDefense China Military Power Report...4/
Nor to vast majority of leading informed sources on this like Ochmanek, the @RANDCorporation Scorecard, @CNAS, etc. This is esp salient b/c co-authors by their own admission have v little insight into contemporary military issues. & both last served in govt in Bush 43. 5/
This is an excellent report, and I'm glad to have joined the study group. The central focus on avoiding war is understandable--a US-China war would be catastrophic and should be avoided. But protecting Taiwan's security and prosperity requires doing more. 1/x https://t.co/P0Sg4LJcpV
— Bonnie Glaser / \u845b\u4f86\u5100 (@BonnieGlaser) February 12, 2021
Normally as it might seem churlish to be so critical, but @cfr is so high-profile & the co-authors so distinguished I think it’s key to be clear. If not, people - including in Beijing - could get the wrong idea & this report could do real harm if influential on defense issues. 2/
BLUF: The defense discussion in this report does not engage at the depth needed to add to this critical debate. Accordingly conclusions in report are ill-founded - & in key parts harmful/misleading, esp that US shldnt be prepared defend Taiwan directly (alongside own efforts). 3/
The root of the problem is that report doesn't engage w the real debate on TWN defense issues or, frankly, the facts as knowable in public. Perhaps the most direct proof of this: The citations. There is nothing in the citations to @DeptofDefense China Military Power Report...4/
Nor to vast majority of leading informed sources on this like Ochmanek, the @RANDCorporation Scorecard, @CNAS, etc. This is esp salient b/c co-authors by their own admission have v little insight into contemporary military issues. & both last served in govt in Bush 43. 5/
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1/ Some initial thoughts on personal moats:
Like company moats, your personal moat should be a competitive advantage that is not only durable—it should also compound over time.
Characteristics of a personal moat below:
2/ Like a company moat, you want to build career capital while you sleep.
As Andrew Chen noted:
3/ You don’t want to build a competitive advantage that is fleeting or that will get commoditized
Things that might get commoditized over time (some longer than
4/ Before the arrival of recorded music, what used to be scarce was the actual music itself — required an in-person artist.
After recorded music, the music itself became abundant and what became scarce was curation, distribution, and self space.
5/ Similarly, in careers, what used to be (more) scarce were things like ideas, money, and exclusive relationships.
In the internet economy, what has become scarce are things like specific knowledge, rare & valuable skills, and great reputations.
Like company moats, your personal moat should be a competitive advantage that is not only durable—it should also compound over time.
Characteristics of a personal moat below:
I'm increasingly interested in the idea of "personal moats" in the context of careers.
— Erik Torenberg (@eriktorenberg) November 22, 2018
Moats should be:
- Hard to learn and hard to do (but perhaps easier for you)
- Skills that are rare and valuable
- Legible
- Compounding over time
- Unique to your own talents & interests https://t.co/bB3k1YcH5b
2/ Like a company moat, you want to build career capital while you sleep.
As Andrew Chen noted:
People talk about \u201cpassive income\u201d a lot but not about \u201cpassive social capital\u201d or \u201cpassive networking\u201d or \u201cpassive knowledge gaining\u201d but that\u2019s what you can architect if you have a thing and it grows over time without intensive constant effort to sustain it
— Andrew Chen (@andrewchen) November 22, 2018
3/ You don’t want to build a competitive advantage that is fleeting or that will get commoditized
Things that might get commoditized over time (some longer than
Things that look like moats but likely aren\u2019t or may fade:
— Erik Torenberg (@eriktorenberg) November 22, 2018
- Proprietary networks
- Being something other than one of the best at any tournament style-game
- Many "awards"
- Twitter followers or general reach without "respect"
- Anything that depends on information asymmetry https://t.co/abjxesVIh9
4/ Before the arrival of recorded music, what used to be scarce was the actual music itself — required an in-person artist.
After recorded music, the music itself became abundant and what became scarce was curation, distribution, and self space.
5/ Similarly, in careers, what used to be (more) scarce were things like ideas, money, and exclusive relationships.
In the internet economy, what has become scarce are things like specific knowledge, rare & valuable skills, and great reputations.
I just finished Eric Adler's The Battle of the Classics, and wanted to say something about Joel Christiansen's review linked below. I am not sure what motivates the review (I speculate a bit below), but it gives a very misleading impression of the book. 1/x
The meat of the criticism is that the history Adler gives is insufficiently critical. Adler describes a few figures who had a great influence on how the modern US university was formed. It's certainly critical: it focuses on the social Darwinism of these figures. 2/x
Other insinuations and suggestions in the review seem wildly off the mark, distorted, or inappropriate-- for example, that the book is clickbaity (it is scholarly) or conservative (hardly) or connected to the events at the Capitol (give me a break). 3/x
The core question: in what sense is classics inherently racist? Classics is old. On Adler's account, it begins in ancient Rome and is revived in the Renaissance. Slavery (Christiansen's primary concern) is also very old. Let's say classics is an education for slaveowners. 4/x
It's worth remembering that literacy itself is elite throughout most of this history. Literacy is, then, also the education of slaveowners. We can honor oral and musical traditions without denying that literacy is, generally, good. 5/x
As someone\u2019s who\u2019s read the book, this review strikes me as tremendously unfair. It mostly faults Adler for not writing the book the reviewer wishes he had! https://t.co/pqpt5Ziivj
— Teresa M. Bejan (@tmbejan) January 12, 2021
The meat of the criticism is that the history Adler gives is insufficiently critical. Adler describes a few figures who had a great influence on how the modern US university was formed. It's certainly critical: it focuses on the social Darwinism of these figures. 2/x
Other insinuations and suggestions in the review seem wildly off the mark, distorted, or inappropriate-- for example, that the book is clickbaity (it is scholarly) or conservative (hardly) or connected to the events at the Capitol (give me a break). 3/x
The core question: in what sense is classics inherently racist? Classics is old. On Adler's account, it begins in ancient Rome and is revived in the Renaissance. Slavery (Christiansen's primary concern) is also very old. Let's say classics is an education for slaveowners. 4/x
It's worth remembering that literacy itself is elite throughout most of this history. Literacy is, then, also the education of slaveowners. We can honor oral and musical traditions without denying that literacy is, generally, good. 5/x
