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Author: Manlobbi 🐝🐝🐝 HONORARY
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Number: of 12641 
Subject: OT: Dunning-Kruger effect
Date: 03/13/2025 3:39 PM
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This video explains the phenomena. Shortly speaking, competence and confidence are often inversely related at the two extremes of the spectrum:

https://youtu.be/JpMreN8dceE?si=LwlnxFvCz2cY_UZZ

Whilst typically not framed as related this to investing, our overconfidence may drive us to make impulsive trades, ignore diversification, or become afraid of or charmed by ”in the moment” themes, without objective analysis, increasing our exposure to permanent losses, and long-term underperformance of index funds.

The quick and dirty method to avoid the problem is to stick purchasing buainesss that you have expertise in, or deep knowledge of the industry.

This is a subtly different variation to Buffett’s way of explaining the solution as sticking to businesses that you "understand". I make the distinction here that we may think we understand something when we lack competence with it, whilst underestimating how much we understand about industries that we have strong knowledge about.

The related problem is that we have difficulty determining what we have strong knowledge about and where we have little or no competence. So a mental test might be extra careful to remain not just the boundary of our competence, as Buffett puts it, but try to move into an even smaller boundary of industries (a smaller circle within the circle) where we have objectively superior knowledge. In those industries we we have lower confidence (according the the phenomena), allowing us to enter investments with a more critical analysis, and with crucial insights, that others taking the opposite trade have skipped.

- Manlobbi
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Author: Texirish 🐝🐝  😊 😞
Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/13/2025 4:39 PM
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This post by Manlobbi is far from OT. So do yourself a favor by listening to - and thinking about - the 25 minute video he links. The presenter uses a lot of multi-syllable language. But the basic message is simple. If you think you really understand something, dig deeper. Then you'll begin to learn what you don't know. And then you'll make better decisions.

It clearly applies to investing. And we're now getting an object lesson on how it applies to politics - which kicks-back on economics, and thus investing. I am deeply concerned that we're about to learn a damaging lesson about how the Dunning-Kruger effect is now impacting the world. And this from a guy - me - who continues to try to keep politics off the BRK board.

So, thanks Manlobbi for sharing. I hope we are listening.

I'm forwarding the link to two groups of family members. One is our daughter and son-in-law, who will soon be retiring and having to become more skilled in investing. The other is our two grand-daughters - to promote their continued learning about human nature. The earlier you think about such things, the more valuable they become.






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Author: tairbear00 🐝🐝  😊 😞
Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/14/2025 3:56 PM
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Texirish, I too, am very much appreciative of Manlobbi for providing the link that identifies the name of this disorder and will share this link with my kids and grandkids! I've oft been guilty of this at times as well...usually during heated discussions (in which at almost age 75, I no longer care to participate, here or anywhere else!).

I've experienced this phenomenon throughout most of my life, especially in businesses I developed (with the help of many others, much more capable and expert than myself, especially in aviation technical matters). When a senior staff member would sheepishly present, with confidence, a solution to a complex matter, I would quietly ask "Are you speaking beyond your knowledge?" This was also the same question I later had for my kids and grandkids. And, wouldn't you know...they (and my staff) turned this around on ME...harumph!!! Now I FINALLY know what to call my disorder, thanks Manlobbi!!

Anyone who has held even the briefest conversation with Manlobbi is well aware that this complex does not remotely apply to this very thoughtful, humble, kind, charitable, and brilliant man! I have a grandson who I hope follows Manlobbi's example. My grandson taught himself calculus at the age of ten, programs computers, is interested in Quantum Mechanics hopes to soon play piano in concert, acts and sings in community plays...yet remains well-grounded. I'm hoping he's a mini-Manlobbi!! (OK... Grandpa tair has to proudly brag a little!).

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Author: Texirish 🐝🐝  😊 😞
Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/14/2025 4:30 PM
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Anyone who has held even the briefest conversation with Manlobbi is well aware that this complex does not remotely apply to this very thoughtful, humble, kind, charitable, and brilliant man! I have a grandson who I hope follows Manlobbi's example. My grandson taught himself calculus at the age of ten, programs computers, is interested in Quantum Mechanics hopes to soon play piano in concert, acts and sings in community plays...yet remains well-grounded. I'm hoping he's a mini-Manlobbi!! (OK... Grandpa tair has to proudly brag a little!).

tailbear,

Thanks for joining in on this discussion. I think this is a very important point that we'll probably all encountered but couldn't put a name to. It deserves more attention.

My version of it was dealing with the mental models of operating managers during my decade of strategic planning. They had been successful based on their particular model, so were reluctant to change - or even challenge - it. But the world changes, and assumptions that led to success in the past may no longer hold about the future. Many examples - GM on cars and IBM on computing are just a couple.

I absolutely agree with your charitization of Manlobbi. And you're certainly forgiven for bragging on your grandson!! Seems well deserved. I strongly suspect the members of this board could contribute many more examples of exceptional offspring. I might be tempted to join in if a thread develops. (Not trying to start one.) But given the type of investors Buffett and Berkshire attract, it shouldn't be a surprise to us.

There's a lot impacting investment decisions that could be shared on this board besides the specifics of Berkshire and betting puts and calls on such. Maybe Manlobbi will help expand our horizons. I think he has. So has Jim at times.

Tex


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Author: mungofitch 🐝🐝🐝🐝🐝 BRONZE
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Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/14/2025 5:11 PM
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Maybe Manlobbi will help expand our horizons. I think he has. So has Jim at times.

Or shrinking them.
It has taken me many years of diligent (and occasionally expensive) study to achieve my current level of ignorance about most investments.

Jim
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Author: Brickeye 🐝🐝🐝  😊 😞
Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/14/2025 8:41 PM
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A good way of combating Dunning Krueger is just following Socrates famous advice- "I must be smart, I know that I know nothing". You get the benefit of feeling smart while looking down on people that actually believe they're smart:-)
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Author: Umm 🐝🐝 HONORARY
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Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/15/2025 3:59 AM
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To be fair, while the Dunning Kruger effect instinctively seems like it would explain a lot, there is an argument that it is nothing more than an artifact of the way the initial study was done:

https://www.scientificamerican.com/article/the-dun...
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Author: Manlobbi 🐝🐝🐝 HONORARY
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Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/15/2025 9:24 AM
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.. there is an argument that it is nothing more than an artifact of the way the initial study was done:
https://www.scientificamerican.com/article/the-dun...


Ignore my post here (which descends even further OT) if you want to relate the Dunning-Kruger effect to investing, which Texirish already nicely started to do. In the above study, Eric Gaze claims that the Dunning-Kruger effect is an artifact of its own design rather than an artifact of human nature.

Eric Gaze, a senior lecturer in mathematics, designs a counter-experiment to prove his claim. I am pretty sure that Eric Gaze got the maths right. His conclusion matched what would be expected. However it seems that he got the interpretation of his own counter-experiment wrong in how the random data was formulated.

Rather than using real people he used imaginary people with random data - they firstly (1) all had received completely logic scores in their tests, and secondly (2) they also had random predictions as to how they scored compared to the others.

Eric Gaze's hypothesis was that the Dunning-Kruger effect is an artifact of research design, not human thinking, and that he and his colleagues would try to show that it can be produced using randomly generated data.

He indeed confirmed his hypothesis, writing in his summary: “To establish the Dunning-Kruger effect is an artifact of research design, not human thinking, my colleagues and I showed it can be produced using randomly generated data.”

He then showed that, like the real people, the Dunning-Kruger effect showed that the low scoring imaginary people - even with this random data - overestimated their score.

Rather than “randomly generated data” producing a balanced popuation, he created a insanely delusional population - by definition of their predictions having a 0% correlarion to their actual scores. Real humans aren’t great at predicting how they rank, but thank goodness, they are not *that* bad.

But intead of a pouplation of accurate predictors, Mr. Gaze put his imaginary delusional people (noting that the two-step randomization produces even less realistic-predicting people than what we get with real huamns) through the Dunning-Kruger experiment, and wanted to show that even with random data - the same Dunning-Kruger effect would be produced. And what do you know.. that’s what it did - because the random sampled data was even more insane than real humans.

He doesn’t cite the randomly generated people as really bad predictors of their competence, and the impression is left that they are just random, thus ordinary, people.

If this point had clicked, I expect Gaze would have called the counter-experiment off. Gaze, in using random data, is not producing a neutral population (similar as random stock pickers are indeed neutral - in this case they are as good as average), but rather a baseline of humans dramatically poor (by construction of the data) at predicting their relative level of competence.

Gaze wanted to deduce that if the Dunning-Kruger experiment brings similar results with the random data, as it does with real people, then it is just the experiment design that is causing the results and not the human nature.

I may understand Gaze's inspiration. Sometimes when doing experiments, you produce results that are inherent to the design of the experiment itself. An example, the bottom 25% performers in the Dunning-Kruger experiment - even if the population were an imaginary population capable to accurately predict their relative ranking - would actually over-predict their scores. This is owing to the lower 25% (by score) inadvertently producing a sub-sample population that, by definition, has a greater performance delta to the average, and thus this skews them to have a larger score delta to the average, thus causing them to also have a larger average over-prediction of their rank, compared to the whole population. However, the effect of this skewing is more mild than what occurs in the experimental results (using real humans), showing that the Dunning-Kruger effect is genuine.

If he wanted to contradict the experiment he would need to construct thre counter-experiment differently. He could use an imaginary population of humans actually fairly good at working out their level of competence (rather than a population dreadfully bad at it, as he did) which could easily be defined mathematically, and then try to show that the Dunning-Kruger effect brings similar results to the real population. That would actually show that the interpretation (the lower scoring 25% greatly overestimating themselves) of the experiment is at fault. It wouldn’t though. Unlike the randomly generated data, the lower 25% would here know they were the lower 25%.

- Manlobbi
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Author: rayvt 🐝  😊 😞
Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/15/2025 9:44 AM
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To be fair, while the Dunning Kruger effect instinctively seems like it would explain a lot, there is an argument that it is nothing more than an artifact of the way the initial study was done:


If you have any inclination to doubt that the Dunning-Kruger effect does not describe a real thing, go to youtube and put these in the search bar:
"sovereign citizen" or "flat earth".
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Author: Uwharrie   😊 😞
Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/15/2025 11:18 AM
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While it is good to see the new data concerning and partially dismantling the Dunning-Kruger Effect thesis, we investors should always question our circle of competency. In other words, it is often healthy to assume we may not know as much as we feel we do. The great Daniel Kahneman said something to the effect every new initiative in an organization should also be evaluated by a group deliberately assigned to attack the assumptions, spreadsheet numbers, etc. of the new initiative. There have been times in my business life when we would have benefited from having had such as process rather than proceeding to spending lots of money and time to later have the marketplace shoot down our faulty assumptions with little or no sales of what we thought was going to be a needed product.

Kahneman also said something to the effect humans are blindly optimistic in their business assumptions and this is where entrepreneurs arise. My recollection is Kahneman said without this blindly optimistic quality many companies and initiatives would never happened. I guess a form of Dunning-Kruger Effect is built into many folks mental programming.

I also seem to recall reading Kahneman saying his thought and research partner, Amos Tversky, was nearly always the smartest person at a gathering and if you were a person who failed to see that, you were the dumbest person in the room. Interesting comment. Tversky did some courageous deeds during his military service engagements. He was a very smart person who was also capable of taking decisive action.

At any rate, my biggest failings have been to not buy particular stocks when my evaluations said they were positioned well for the future. This has usually been because they never got cheap enough to meet the Buffett 10:1 Market Cap to Pre-Tax earnings threshold. I've recently been reviewing this area and wonder if a 11:1 or maybe a 12:1 ratio would have served me better as I would gotten nearly all of the ones that have gone on to do quite well over the years. I welcome hearing your thoughts about stretching Buffett's Margin of Safety ratio a bit higher. A note: I think the use of this type of ratio helps with dampening the bias and blindness of investors like me as most companies with little debt, long-running established products or services that get down to the 10:1 ratio generally do well in the long term assuming they are not in a declining industry or beset with intractable legal or competitive challenges.

Thoughts?

Uwharrie
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Author: newfydog 🐝🐝  😊 😞
Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/15/2025 12:41 PM
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I've recently been reviewing this area and wonder if a 11:1 or maybe a 12:1 ratio would have served me better as I would gotten nearly all of the ones that have gone on to do quite well over the years. I welcome hearing your thoughts about stretching Buffett's Margin of Safety ratio a bit higher.

Warren has said some to the effect of "I'm very happy for people who make lots of money their way, in businesses they understand, but we will stick with our methods and be happy with a reasonable return". I have often felt he was too shy about jumping on opportunities, but in the long run I can't complain.
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Author: Lambo 🐝  😊 😞
Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/16/2025 9:06 AM
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I remember reading a recap of the original experiment and I was taken by this, IIRC. After the test and asking the opinion of those who scored low but had a high opinion of how they scored, they told then their scores, and it wasn't dealt with well, but in a very shot period of time, they were back to having a high opinion of their knowledge in the area. So they then give them classes and only after taking the classes did they realize how poor their knowledge was in areas of the subject. This sequence astonished me. I remember taking classes where they tested the class the first day to see where to place an emphasis on the teaching, and now I wondered how I did. I consider myself a terrible investor and follow other people's advice and am now in lots of cash at 73 due to that. :) I get stressed if I make changes as I see myself as not knowing what I am doing.

But on reading the recap I remember thinking - How do you test people on humor? Just how do you test that? I'd like to take that test and see how I do. You gave a class on humor? How do you teach a class on humor? I want to take that class and improve my understanding of humor. I'm curious as to how they chose humor as something to be tested. I might agree with them. :)

I actually miss the humor board from the old Motley Fool. I made friends with Average Joe before he got booted off the board and went down to see him with my wife. He's now in a care home and I'd like to see him before he passes.
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Author: proftalon   😊 😞
Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/16/2025 9:38 AM
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The eminent British guitarist John McLaughlin once said, "The older I get, the less I know."

professor talon
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Author: wopger   😊 😞
Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/16/2025 10:49 AM
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You can also relate the Dunning-Kruger effect to Ben Graham's “In the short run, the market is a voting machine but in the long run, it is a weighing machine”.

I wonder what the consequences are when people who overestimate their own abilities make a career in business or politics.
By overestimating yourself, you can inspire others, sweep them along, find capital and supporters and expand your sphere of influence more and more (voting machine).

However, none of this changes the real abilities, only the opinions about them.
For example, I still can't build a new and great airplane just because I think I'm an outstanding aircraft engineer.

In the long term, the weighing machine will have to take control again and bring down "solutions" that don't work.
Until then, however, many resources will be directed in the wrong direction.

I ask myself the following questions
- how long can such dysfunctional systems be maintained? (probably for a very long time)
- will this lead to more frequent, longer and ever larger boom-bust cycles?
- can such mismatches between appearance and reality be recognized in time?
- can the resulting inefficiencies (price vs. value) on the stock market be exploited?
- is it enough for your own success if you can at least recognize the biggest impostors and stay away from them? (I hope so)
- am I overestimating my abilities in this respect? (very likely)

wopger

(translated from German into English with the help of deepl.com)
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Author: mungofitch 🐝🐝🐝🐝🐝 BRONZE
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Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/16/2025 12:38 PM
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- how long can such dysfunctional systems be maintained? (probably for a very long time)

I think that life is so interesting in part because this varies so much depending on the subject area in question.

Some incompetents have their reputations last throughout their careers of applying it, and some time beyond, before people figure out that they weren't actually good. The Jack Welch effect?
In your example of aircraft engineering, I suspect the faking-it window is pretty short. Ironically, that's one of the many businesses that GE was in, but the people in that division were pretty good.

Jim
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Author: rayvt 🐝  😊 😞
Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/16/2025 1:32 PM
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I ask myself the following questions
...
- am I overestimating my abilities?


I once wrote a very clever & complicated section of C code, and put in the comments of that section "I hope I am as clever here as I think I am".

A few years later, one of our junior programmers happened to be perusing that code and busted out laughing. She came to my office and said "I guess you were, because that code has never had a problem."

But to this day I always put that comment in a complex chunk of code.
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Author: tairbear00 🐝🐝  😊 😞
Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/16/2025 2:44 PM
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Brickeye wrote:
A good way of combating Dunning Krueger is just following Socrates famous advice- "I must be smart, I know that I know nothing"


"To know what you know and what you do not know, that is true knowledge"
(Various iterations attributed to Confucius, Loa Tzu, Socrates, et al)

I have to keep reminding myself of this and other quotes! (I posted this quote on my office wall over 45 years ago, providing copies to my kids and grandkids throughout the years).

I ran into Quantum Mechanics (Nee Quantum Physics) as an amateur just over 40 years ago via John Gribbin's book, "In Search of Schroedinger's Cat". 40 years later, still an amateur reading more and still counting, it's become abundantly clear to me that I don't know anything AT ALL!

https://www.amazon.com/Search-Schr%C3%B6dingers-Ca...


Links to some of my favorite quotes that help keep me a bit humble:

https://www.goodreads.com/author/quotes/2622245.La...

https://www.brainyquote.com/authors/lao-tzu-quotes


tairbear
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Author: Said   😊 😞
Number: of 12641 
Subject: Re: OT: Dunning-Kruger effect
Date: 03/16/2025 2:52 PM
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And I once wrote in 6502 assembler a super-flexible quicksort routine that could sort every kind of data arrays, integers, strings etc. I optimised and optimised it, before I finally showed it to a fellow programmer I highly respected, proclaiming:

"This routine is perfect! There is not one superfluous byte. You won't be able to shorten it by a single byte!"

After looking for less than 1min at the code he said "This comparison here: If you do it like this.... it's one byte shorter". Deeply humbling.
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