No general method to detect fraud
calpaterson.com
calpaterson.com
It is a hell of a way to live.
Most people don't want anything from you. Some people like just chatting. Salesmen will feel smothering and uncomfortable because they want something from you. Advertisements trigger me because it's so obvious (in my mind) they want something from you. News feels this way too.
How can I tell? The same cues that fool people who focus on the surface-level: flashiness, bravado, loudness, taking the subject matter to things I do not care about. Trying to make me feel emotions (fomo, FUD, even excitement).
You could use it as dating advice: people are turned off when you want something from them too much.
Not all that glitters is gold.
For anyone that actually thinks in this way, as I do, I recommend seeking help. It took me half my life to actually get help and I realized after being on medication just how bad my anxiety was. It is good to be cautious, but when you see daggers everywhere it is probably time to get help.
I don't need to live in constant fear of the worst, but it helps to be prepared for it
"prepare for the worst" is super vague, because the worst is unbounded in implausibility.
In practice though for most goals it's probably better to trade off Type 1 vs Type 2 error.
This goes against Hanlon's razor, though.
I do not try to think in this way. I wish I didn’t.
Also we often underestimate others when thinking too cautiously or fearful. This can often be cured through direct interaction.
Whenever I feel overwhelmed by negative perspective/thinking. I try one of these angles. Sometimes it works, especially if I put effort into engaging with people that are involved.
His takeaway is that society is a pretty bleak place when we all lose our “default to trust” mode of operation.
> It is a hell of a way to live.
True, but it is the honest way to live. Especially employment/management relationships are all about manipulating, cajoling, and ultimately threatening (by homelessness and starvation) people into doing things they would not otherwise do. Things are not much better in private/social life, except maybe within some families / friend groups or between lovers during the first year or so. Life is so bleak.
In addition it is too reductive and doesn't represent the very complex (even enjoyably subtle) interactions that go on between humans who do want something from each other.
Life has many illusions and it is up to you which one you pick. The reality you are enduring is just another illusion you've settled on: except it's a crap one.
I don't manipulate them, there are no dark patterns on my web site, I don't hold their data hostage or nickel and dime them.
I'd not heard this stated so clearly before.
Part of this is because you have to pay the salaries of the investigators, so there is a cost of detection. It's not worth recovering an amount that is less than the cost of an investigation. Secondly, a company will lose customers if it has a reputation for having too many false positives or a default stance of mistrust of their policyholders.
It's wonderful to not have to trust too much. Instead to rely on evidence and have a contingency if things go horribly south.
Did the IETF miss a vulnerability when they inveted the protocol? Was there someone on the team planted by the NSA? Do the cert authorities provide the means to hack my data in some way?
I don't think they do but that is because I trust them that I don't think it would be in their interest to do this and I think that if the IETF messed with the protocol, someone would have noticed but we have seen OpenSSL bugs that have sat there for years because it was too complex for most people to understand.
It just sounds like turtles all the way down because ultimately you have to trust someone or something even if it is just time and experience.
That's why an effective police, punishment for business crimes, and law enforcement even when the person moves into a different place are important. A more trusting society is a happier and richer one, so we should make it easy to trust.
I guess I need to read up on the Monty Hall problem again, because I always thought it was 1/2 chance if you switch (vs 1/3 chance if you don't).
100 doors, 1 car, 99 goats. Pick a door. All doors open (with goats except 1) ... Do you think you picked the 1/100 door with the car, or that it's the other only one left standing.
I can make sense of it by drawing out the probability trees and see that it's 1/2 rather than 2/3 in this case, but it actually sticks with me if I think more like so:
My prior is that there's a 1/3 chance I picked the car; that's the world where the host can't reveal anything other than a goat.
In the scenario where the host then reveals a goat intentionally, my prior doesn't change. The host can always reveal a goat. This gives me no information. Therefore, it's still 1/3 that I picked the car, so the remaining door must be 2/3, so I switch and get a 2/3 chance.
But in the scenario where the host reveals a door at random, and it happens to be a goat, it's time to update my priors. Since he didn't accidentally reveal the prize, the probability that I'm in the world where he couldn't accidentally reveal the prize is increased relative to the probability that I'm in the world where he could have.
Maybe. Maybe you insta-lose. Maybe you insta-win. It doesn't matter. (But by definition if the host picks a door at random, there is a possibility that they will pick the door with the prize behind it, so something must happen in that case).
> I'm saying as long as he doesn't accidentally open the prize door, it doesn't matter.
But that's false. If the host picked the door to reveal at random then your chance is 1/2 if you switch and 1/2 if you keep your original door. The 1/3-2/3 case only happens if the host deliberately picked a door that didn't have the prize.
import java.util.List;
import java.util.Random;
import java.util.stream.Collectors;
import java.util.stream.Stream;
public class MontyHall {
public static void main(String[] args) {
Random random = new Random();
final boolean GUEST_ALWAYS_SWITCHES = true /* change guest strategy */;
final boolean HOST_IS_DRUNK = false /* simulate host knowledge */;
final boolean GUEST_WINS_IF_HOST_PICKS_PRIZE_BY_ACCIDENT = true;
final double GAME_COUNT = 1_000_000;
double winCount = 0;
for(int i = 0; i < GAME_COUNT; i++) {
List<String> remainingDoors = Stream.of("A", "B", "C").collect(Collectors.toList());
String prizeDoor = remainingDoors.get(random.nextInt(3));
String guestInitialPick = remainingDoors.remove(random.nextInt(remainingDoors.size()));
String hostPick;
if(HOST_IS_DRUNK) {
hostPick = /* host picks random */ remainingDoors.remove(random.nextInt(remainingDoors.size()));
}
else {
// host is sober and always opens empty door
hostPick = remainingDoors.get(0).equals(prizeDoor) ? remainingDoors.remove(1) : remainingDoors.remove(0);
}
if(hostPick.equals(prizeDoor)) {
if(GUEST_WINS_IF_HOST_PICKS_PRIZE_BY_ACCIDENT) {
winCount++;
}
continue /* insta win/loss */;
}
// guest decides to stick with inital pick or switch
String guestFinalPick = guestInitialPick;
if(GUEST_ALWAYS_SWITCHES) {
guestFinalPick = remainingDoors.get(0);
}
if(guestFinalPick.equals(prizeDoor)) {
winCount++;
}
}
System.out.println(String.format("Win rate: %.2f", winCount / GAME_COUNT));
}
}In the if(hostPick.equals(prizeDoor)) block, rather than maybe incrementing winCount, you need to decrement GAME_COUNT (or rather the number that you're going to divide by at the end - don't reduce the number of iterations) - we're talking about the probability when you're deciding whether to switch (so after the host has already opened the door and not hit the prize).
I'm always talking about the probability of winning the complete game when sticking to a certain strategy. I never look at intermediate probabilities.
Decrementing the game count or the divisor would be the like crossing out or ignoring decision tree branches.
If you change the game rules and say the game is repeated if the drunken host picks the prize, then the simulation would have to repeat until the guest has either won or lost, but the game count would still remain the same (= the number of times a simulated guest is invited to the game show).
Well, it does matter unless you have the rather unusual rule that you win if the host reveals the prize - normally it would make a lot more sense to say you lose in that case. (In fact this is the deep reason why switching works in the original problem - if you switch, then you win if a blind host "would have" revealed the prize, whereas if you don't switch, you lose).
The relevant general fact is that if the host is blind, your strategy never makes any difference.
> Decrementing the game count or the divisor would be the like crossing out or ignoring decision tree branches.
Well, there is no decision to be made if the host revealed the prize - you never get the choice of whether to switch or not. When we ask about the probabilities after a certain choice, at the point where you're making that choice you already know that you've certainly had to make that choice. Otherwise could equally well say that you have to include the probability of getting through to the final round, the probability of getting onto the gameshow in the first place, ...
(Edit: sorry that was not your statement, but that from furyofantares.)
Now you agreed that it is still 2/3, so I still stand by my statement "As long as the host doesn't accidentally open the prize door, it doesn't matter whether he forgot or not."
> Well, it does matter unless you have the rather unusual rule that you win if the host reveals the prize
If you change the game and say the host is blind, you have to also make a rule about what happens if the blind host reveals the prize. Otherwise how could you decide on a strategy as a guest?
> Well, there is no decision to be made if the host revealed the prize
No chance for the guest to switch, yes, but it is still a branch in the whole probability tree, and you have to count it either as a win or a loss for the guest. They can't just all go home and pretend the show didn't happen.
> Otherwise could equally well say that you have to include the probability of getting through to the final round, the probability of getting onto the gameshow in the first place, ...
The problem statement is: "What strategy (stick or switch) is best for the guest (= has higher probability to win), provided he gets into the game show final." No ambiguity here.
The most natural rule is that the guest loses: the guest picked a door that didn't have the prize, they get what's behind "their" door. (And note that the much-argued formulation already "changes" the game from what was done on the original gameshow).
> The problem statement is: "What strategy (stick or switch) is best for the guest (= has higher probability to win), provided he gets into the game show final."
Why "provided he gets into the gameshow final" and not "provided he gets into the gameshow final and is offered the chance to switch"? Like, if you're asking whether a chess player should take an en passant capture, you'd look at whether capturing or declining en passant leads to winning more often, you wouldn't look at all possible chess games (including those where there was no chance to capture en passant) because that just adds a bunch of irrelevant cases.
I don't want to argue which rule would be more natural or make a more interesting show. But without a clear rule, I cannot decide on a playing strategy.
> Why "provided he gets into the gameshow final"?
Because I assumed that the host always has to open a door and give a choice to switch.
It doesn't make any difference to your strategy! You don't get any choice if the host opens the door and reveals the prize, so your strategy can't possibly be affected by what the payoff for that scenario is - even if you win 10x the prize if that happens, or get executed if that happens, it makes no difference to whether you should switch or not in the scenario where you actually do get given a choice.
But if the rule were to reset the game until the host doesn't make any more mistakes, it matters.
Guest selects a door. If it has a goat behind it, the host opens that door and says "you lose". If the guest initially picks the car, then the host opens a different door and asks the guest if they want to switch.
For the player, if you've reached the point that the host is offering you to switch, there's no way to know whether you are in the case where switching improves your odds to 2/3, keeps them the same, or decreases them to zero.
You responded to someone who said it's back to 50/50 once a random host reveals a goat.
I thought you were contradicting this or adding to it, but if you were saying it doesn't matter if you switch, then yeah, that's what 50/50 means.
If Your first choice was lucky and two goats remained in other gates than Monty does not change anything by showing You the goat in one of them (it't the same as if Monty selected random gate).
Things becomes intresting if You was unlucky and selected Goat. Monty MUST show You the other goat (because there is only one available for him to select). And thus he introduces information to otherwise random selection (it stops beeing random).
And by doing this he eliminates for You conditional possiblity of selecting second goat when You selected one in first round (and in this conditional scenariu swiching is sure bet which changes the overall odds to 2/3)
It's a 1/2 chance if you pick after the second door is opened, regardless of switching.
It's a 2/3 chance if you pick before the second door is open and switch after the second door is opened.
I recommend reading again, because I don't want to write up the logic.
Of a bigger concern is that this was not true on "Let's Make a Deal". The problem assumes that Monty always offered the option to switch. In reality, he did not, and the offers were not random. That corrected for the issue to a large degree in practice.
The basic argument is. If you don't switch, you have 1/3 chance of winning. So if you do switch you have 1/3 chance of losing. Hence if you switch you have 2/3 chance of winning.
How the door you switched too went from 1/3 chance to double is the hard part to explain. But it must be the case.
If you start the game with the intention of switching, you have a 2/3 chance of being successful because the winning strategy is to miss the car on your first pick.
Regardless of your intended plan, you only had a 1/3 chance of picking correctly the first time, so switching gets you a 2/3 chance.
When you choose initially, you have a 1/3 probability of getting the right one, leaving a 2/3 probability that the car is on one of the other two.
The host reveals one of the other two. So that 2/3 probability applies to the remaining door. Here is a short C implementation that made it very clear to me...
#include <stdio.h>
#include <stdlib.h>
int doround () {
int car = rand() % 3;
int firstchoice = rand() % 3;
// host reveals one of the goat doors
if (car == firstchoice) {
// you changing to the other door after the reveal is a loss
return 0;
}
if(car != firstchoice) {
// you changing to the other door after the reveal is a win
return 1;
}
}
int main(int argc, char** argv) {
int wins=0;
for (int round=0; round < 1000; round++){
wins+=doround();
}
printf("Worked in %d of %d rounds\n", wins, rounds);
}I thought through it again, and I'm angry now.
At least I'm not alone (got this link from the article): https://web.archive.org/web/20140413131827/http://www.decisi...
Goat. | Car. | Goat.|.
Goat. | Goat. | Car.|.
The above tables shows all possible distribution of car and goats. If the initial choice was Door A, then you only have 1/3 probability. But after B/C door is opened the probability increases to 2/3 if switched.
The clue is that the host will always open the door with a goat.
My way of personally looking for fraud is to look at incentives. What might this person stand to gain if I take this chosen action and do my incentives align in any way with his?
As the article says, his clever angle was not to over-inflate the ROI of the investments which might well make them look implausible.
What is harder to spot is whether an investment is actually taking place.
The incentive view is a good one, and one often followed by auditors, starting with the pay of company accountants!
8-12 months severence / perf bonus, glowing reference for taking one for the team, and placement services. It's just like normal attrition, but makes planning a scam and consolidating a lot of anti-patterns way less viable.
It seems psychotic, but compared to the incidence of mendacity, it's a pretty good deal for everyone.
This is a good way to detect fraud. Basically, any number set will tend to have more 1,2,3's vs 7,8,9. Fraudsters will use random data that doesn't follow this.
Interesting to link this to https://news.ycombinator.com/item?id=27467999 (hedgehogs/foxes and "one big idea"); the people with one big idea, who are aficionados of that idea, are easier to exploit because they're using the idea to avoid being contingent: that is, they're not looking at what's actually happening, merely whether they can fit the idea to it.
Following this, a lot of modern social media culture war consists of (a) selling you a universal idea that explains everything you see in the media and then (b) recruiting you into a cult which uses your support (money, votes) for their own gain. The ur-example is of course Nazism selling the idea that Jews were the problem to which they had the "solution", but you can see analogies to this all over the political spectrum.
No, you can see analogies of this specifically on the right, which is just doing the same thing still.
"Please use the original title, unless it is misleading or linkbait; don't editorialize." https://news.ycombinator.com/newsguidelines.html
The article itself looks good though!
Glad you liked it though.
Ah, like the New York Times. No worries :)
Similarly, ransomware is doing us all a favor. Every ransomware hack exposes and closes a vulnerability that could do much more damage in the hands of a truly malicious actor such as an enemy in wartime.
I suppose that - always dangerous to extend an analogy - ransomware is more like "intellectual variolation" than vaccination.
I wonder what would happen in wartime though.