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Heuristics that almost always work

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Re: Heuristics that almost always work

#371

Post by 8note »

323 wrote: post #149
HWR_14 wrote: post #61

Earlier quoted context omitted.

> the mere act of doing it more often dramatically changes the risk. Kind of. However, you already know that the first N outings didn't have a disaster. So those should be discarded from your analysis. Doing it N times more has a lot of risk, doing it the N+1th time has barely any.

This is called the Turkey fallacy: the turkey was feed by humans for 1000 days, and after each feed event he updated his belief that humans care for him until it's now almost a statistical certainty.

hows yesterday's tree impacting today's?

Re: Heuristics that almost always work

#372

Post by borroka »

Spinnaker_ wrote: post #353
borroka wrote: post #275

I read them as sloppy caricatures that provide little value to the conversation. Let's take the security guard: "The only problem is: he now provides literally no value. He’s excluded by fiat the possibility of ever being useful in any way. He could be losslessly replaced by a rock with the words “THERE ARE NO ROBBERS” on it." That is blatantly not true, the guard provide value since the wanna-be robbers don't know w…

You have a very weird idea of what security guards do. They don't sit in front of the entrance all night, scaring off would-be robbers. They are inside the building, in their booth, probably looking over some monitors. They do not provide a deterrent, they just call the cops if something does happen. Robbers have no clue if they are there or not. The heuristic works fine.

I have a very clear idea of what security guards do and I don't know where you got that I believe they "sit in front of the entrance all night" (which they do very often in South America, by the way, among other locations).

Any "reasonable robber", which means maybe not your early teen looking for some adrenaline or the out-of-their-mind tweakers, knows or checks whether there are any security guards in a building in which they intend to make a robbery.

Re: Heuristics that almost always work

#373

Post by analog31 »

jppope wrote: post #2

One of the amazing subtleties in this article... if you're a fast reader you'll stop paying attention to the stories as they go through... kind of amazing that this article is layered like that.

Indeed, I was beginning to wonder if I could replace the blog with a rock.

Re: Heuristics that almost always work

#374

Post by jozvolskyef »

mercutio2 wrote: post #359
jozvolskyef wrote: post #316

Earlier quoted context omitted.

Excess Cancer Mortality per 100,000 individuals exposed to 100mSv is ~1000 in the 1 year-old male cohort. A single scan is ~3mSv, which makes the mortality ~30 per 100k, or 1 in ~3333, assuming the linear no-threshold model[1]. When someone comes to the ER with a traumatic brain injury, a CT scan is the standard practice because they are at a high risk of dying and presumably the scan is important for reducing the ri…

I'm so glad you mentioned the linear no-threshold model. Do you believe in it? I don't, particularly at the single digit mSv level.

At some point there will be enough data from different countries to confidently support or reject it. Until then I see it as the preferred hypothesis by Occam's razor and also because I'd rather err on the side of caution.

Re: Heuristics that almost always work

#375

Post by PaulHoule »

robbedpeter wrote: post #65
PaulHoule wrote: post #6

You'd do a lot better with one strong example rather than seven weak examples. For instance, if you are interested in Bayes Theorem like a lot of rationalists say they are, you could talk about the medical test which is 99.99% accurate but for which 90% of the positives are false positives.

Drug testing is a good example for most people to understand why Bayesian thinking is relevant. https://www.mun.ca/biology/scarr/4250_Bayes_Theorem.html Imagine that a driver gets hit by accident. He's tested as part of company policy, and tests positive. He gets fired, even though the test only really tells us there's a 33.2% chance he was actually using the drug. Real world drug tests are a lot worse than 1% false…

Animals are great at reading people emotionally. Given that the handler has some subjectivity odds are pretty good the handler perceives the dog alerts if the cops are themselves suspicious.

Re: Heuristics that almost always work

#376

Post by throwaway22032 »

alexfrydl wrote: post #145
the_af wrote: post #72

One interesting twist on the doctor example: we know she is almost always right that it's nothing, that it will all go away and that just two aspirins are ok. The article correctly points out that she will miss one or two cases where it was a terrible disease instead, and that her prescription of aspirin and to go away and rest will be misguided. However... doctors must do more than just cure you. They must also "do…

The problem is that people are not statistics. It may sound reasonable on the surface to say that this heuristic minimizes harm on average because she doesn't perform unnecessary interventions on the 99.9%. However, there are still actual human beings in the 0.1% who are harmed. What you're really saying is that if a group of people is small enough, it's fair for them to suffer preventable harm if preventing it would…

There are an unfathomable number of possible things that could be wrong with you at any one time. All of those might not be present in 99% of people and present in 1%.

But the 1% is not the same for every disease. If you perform unnecessary interventions on everyone for every disease, then you also perform unnecessary interventions on the 1% of every disease for all of the other diseases that they don't have.

Now you've given everyone weird cancers because you've done thousands of x-rays and CT scans for all manner of things.

Re: Heuristics that almost always work

#377

Post by [deleted] »

kqr wrote: post #130
PaulHoule wrote: post #113

Earlier quoted context omitted.

Actually https://en.wikipedia.org/wiki/Kelly_criterion "The Kelly bet size is found by maximizing the expected value of the logarithm of wealth, which is equivalent to maximizing the expected geometric growth rate" In real life people often choose to make bets smaller than the Kelley bet. Part of that is that even if you have a good model there are still "unknown unknowns" that will make your model wrong some of the…

I've long found that Wikipedia article woefully lacking in generality. 1) The Kelly criterion is a general decision rule not limited to bet sizing. Bet sizing is just a special case where you're choosing between actions that correspond to different bet sizes. The Kelly criterion works very well also for other actions, like whether to pursue project A or B, whether to get insurance or not, and indeed whether to sleep…

[deleted]

Re: Heuristics that almost always work

#378

Post by refurb »

inglor_cz wrote: post #30

This story reminded me of a story written by a Czech biologist who studied animals in Papua-New Guinea and went to a hunt with a group of local tribesmen. The dusk was approaching, they were still in the forest and he proposed that they could sleep under a tree. The hunters were adamant in their refusal: no, this is dangerous, a tree might fall on you in your sleep and kill you . He relented, but silently considered…

But the odds aren’t additive. If you sleep under a tree 4999 times and nothing happens, that doesn’t mean the 5000 time you sleep under one you’ll get crushed.

Each and every time you have a 1 in 5000 chance.

Re: Heuristics that almost always work

#379

Post by csomar »

1. The guard: He is not even there to protect the store. He is there as a deterrent. Nothing more. The number of people stealing from a guarded store is small, but not 0. The number of people killing the guard to steal a store is really negligible. A store without a guard will get stolen, however.

2. The doctor: This is a true one. I did study medicine and I figured that for most of the time, it is fine. But the doctor here serves an important emotional job to support these people. Some people freak out especially after they did some Internet research or a relative went through the same symptoms.

3. The futurist: Not sure why this one was included. There is all kind of crap in the media. None of it is true. No one is also hiring such a guy unless he is looking at the other outcome (tech that will make it). In that case, I think the guy will be worth a lot more than a rock.

4. Same as 3

5. The interviewer: Most executives know this. That's the job and that's why credentials are a thing.

6. The queen: Should read some history I guess: https://en.wikipedia.org/wiki/1975_Australian_constitutional...

7. The Weatherman: Some are lucky and some have busy jobs. That's life I guess?

Re: Heuristics that almost always work

#380

Post by paulpauper »

csomar wrote: post #379

1. The guard: He is not even there to protect the store. He is there as a deterrent. Nothing more. The number of people stealing from a guarded store is small, but not 0. The number of people killing the guard to steal a store is really negligible. A store without a guard will get stolen, however. 2. The doctor: This is a true one. I did study medicine and I figured that for most of the time, it is fine. But the doct…

Someone who has cancer presumably would see the doc. again, and further tests would be run. Studies show that this delay costs minimal lives, and testing immediately would cost more lives due to possible false positives or complications.
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