Is there any evidence than American or any other legal system is significantly better than chance at what it does? Or even not significantly worse than chance? (by being biased instead of just random)
That’s the first question we should be asking, before concerning ourselves with minor issues about admissibility of evidence.
That’s an excellent question. The answer depends on exactly what you mean by “better than chance.” If you mean “more than half of those convicted of a crime are guilty of that crime,” then I’d say yes, there is excellent reason to think that they are. Prosecutors usually have access to several times more reports of crime than they can afford to go out and prosecute. Prosecutors are often explicitly or implicitly evaluated on their win ratio—they have strong incentives to pick the ‘easy’ cases where there is abundant evidence that the suspect is guilty. Most defense lawyers will cheerfully concede that the vast majority of their clients are guilty—either the clients admit as much to their lawyers, or the clients insist on implausible stories that don’t pass muster, which the lawyers have to disguise in order to get their clients to go free. Although as a matter of law and rhetoric people are presumed innocent until proven guilty, as a matter of cold statistics, someone who has been lawfully indicted in America is probably more likely to be guilty than innocent. In fact, there are probably so many guilty suspects in Court that the legal system does strictly worse than what social scientists call a “naive predictor”—i.e., just assuming that everyone is guilty. Of course, that wouldn’t be a sustainable policy—prosecutors choose easy cases because they know that they’ll be required to win those cases in a relatively challenging environment. If the rule were that everyone is guilty, prosecutors would start choosing cases based on other criteria, and the percentage of indicted suspects who were actually guilty would go down.
Suppose you survey defense attorneys, and conclude that, say, roughly 80% of indicted suspects are guilty. Could you somehow measure whether the legal system does better than a “mixed strategy predictor” that guessed that a suspect was guilty with probability 0.8 and guessed that a suspect was innocent with probability 0.2? The mixed-strategy predictor would get an accurate result in (0.8) ^ 2 + (0.2) ^ 2 = 68% of the time. To assess whether the legal system is better than a mixed-strategy predictor, you would need to have a way of validating at least a sample of actual cases. I really have no idea how you would start to do that. It’s not clear that self-reported guilt or defense-attorney-assessed guilt will correlate strongly enough with actual guilt that we can figure out which individual cases the legal system gets right and which ones it gets wrong. But if you can’t measure accuracy in individual cases, how do you figure out the system’s overall accuracy rate? It’s not clear that looking at appellate results or DNA exonerations, etc. would help either. A reversal on appeal is no guarantee of innocence, because a sentence can be reversed (a) if the evidence is still strong but not strong enough to remove all reasonable doubt as well as (b) when the prosecution or police have used inappropriate but reliable tactics (such as using high-tech cameras to take pictures of the inside of your home without a warrant).
Finally, there is “better than chance” in the sense of specific forensic techniques being verifiably better than, say, a Ouija board. There are several pretty good techniques, such as document analysis, DNA analysis, electronic tracing, and perhaps even paired-question polygraph testing. Whether or not the system interprets the evidence correctly, a typical trial at least contains sufficient evidence for a rational evaluator to beat chance.
[T]here are probably so many guilty suspects (...) that the legal system does strictly worse than (...) just assuming that everyone is guilty.
Careful, there: the economic damage of not locking up a thief is much lower than the economic damage of incorrectly locking up a non-thief. “It’s better that X guilty people go free than that one innocent person goes to prison” is a good principle.
(Note that X is likely to have different values for weed users, thieves and serial killers.)
A thief at large but constrained by trying not to get caught doesn’t do as much net economic damage as destroying the economic, family and social life of an otherwise productive member of society.
For example, it would be almost impossible for a single shoplifter or casual stealer of office supplies to do anything like the economic damage of even removing themselves from the economy and putting them in prison. The only reason we still do it is to discourage behaviour that would seriously hurt the economy if it became the norm.
If you start locking people up with careless disregard for whether or not they are guilty, you get all the economic cost of the prison system but lose the clarity of the signal. The message becomes “hey, you’re probably going to prison at some point anyway. Might as well grab what you can while you are still free to enjoy it”.
The message becomes “hey, you’re probably going to prison at some point anyway. Might as well grab what you can while you are still free to enjoy it”.
I wouldn’t quite expect that, but certainly I agree that if there’s no expectation that punishment correlates better with committing a crime than with refraining from doing so, then punishment loses its deterrent function, which I gather is your real point here.
In addition to that, perception of unfairness in the justice system devalues the social contract between government and individuals. It places the individual in a competing rather than cooperating relationship with social institutions (such as law enforcement), so it’s not a mere lack of deterrence, it’s active encouragement to defect for individual gain at the expense of “the man”.
If you doubt it, ask anyone who lives in a neighbourhood where the cops have a record of incompetence or abuse of authority.
If you start locking people up with careless disregard for whether or not they are guilty, you get all the economic cost of the prison system but lose the clarity of the signal. The message becomes “hey, you’re probably going to prison at some point anyway. Might as well grab what you can while you are still free to enjoy it”.
I’ve heard (anecdotally, not with good evidence) that this is precisely the attitude that many poor urban young black men already have (actually with ‘go to prison’ changed to ‘go to prison or get killed’). Thus one has every reason to join a gang for the immediate services that it provides, future be damned.
If a random 80% of suspects are guilty, the appropriate naive predictor is one that always votes “guilty”, not one that tries to match probabilities by choosing a random 80% of suspects to call guilty. Then you get an accurate result 80% of the time, which is a lot better than 68%. That seems to me a more appropriate benchmark.
(Alternatively, you might consider a predictor that matches its probabilities not to the proportion of defendants who are guilty but to the proportion who are convicted. There might be something to be said for that.)
I think the intended question is whether the legal system adds anything beyond a pure chance element. Somehow we’d need a gold standard of actually guilty and innocent suspects, then we’d need to measure whether p(guilty|convicted) > 80%. You could also ask if p(innocent|acquitted) > 20%, but that’s the same question.
Thank you! Intended or not, it’s a fantastic question, and I don’t know where to look up the answer. I’m not even sure that anyone has seriously tried to answer that question. If they haven’t, then I want to. I’ll look into it.
The closest thing I know of is the “actually innocent, but convicted” sample that gradually came to light under DNA testing of inmates. Unreported crime rates get estimated somehow, so I’d be surprised if nobody had combined those numbers to do a study in this vein. Haven’t found one with a cursory googling, though.
I don’t see how those are “the same question”. If out of 8 accused 4 are guilty and two of them are convicted, the rest acquitted. Than p(guilty|convicted) = 1 and p(innocent|acquitted) = 2⁄3.
The assumption was that 80% of defendants are guilty, which is more than 4 of 8. Under this assumption, asking whether p(guilty|convicted) > 80% is just asking whether conviction positively correlates with guilt. Asking if p(innocent|acquitted) > 20% is just asking if acquittal positively correlates with innocence. These are really the same question, because P correlates with Q iff ¬P correlates with ¬Q.
It proves that mistakes have been made, but in the end, no, I don’t think it’s terribly useful evidence for evaluating the rate of wrongful convictions. Why not? There have been 289 post-conviction DNA exonerations in US history, mostly in the last 15 years. That gives a rate of under 20 per year. Suppose 10,000 people a year are incarcerated for the types of crime that DNA exoneration is most likely to be possible for, namely murder and rape (I couldn’t find exact figures, but I suspect the real number is at least this big). Then considering DNA exonerations gives us a lower bound of something like .2% on the error rate of US courts.
That is only useful evidence about the error rate if your prior estimate of the inaccuracy was less than that, and I mean, come on, really? Only one conviction in 500 is a mistake?
DNA exoneration happens when one is innocent and combination of extremely lucky circumstances make retesting of evidence possible. The latter I would be shocked to find at higher than 1:100 chance.
The appellate system itself—of which cases involving new DNA evidence are a tiny fraction—is a much more useful measure.
There are a whole lot more exonerations via the appeals process than those driven by DNA evidence alone. This aught to be obvious, and the 0.2% provided by DNA is an extreme lower bound, not the actual rate of error correction.
Case in point, I found an article describing a study on overturning death penalty convictions, and they found that 7% of convictions were overturned on re-trial, and 75% of sentences were reduced from the death penalty upon re-trial.
One in fourteen sounds a lot more reasonable to me, and again that’s just death penalty cases, for which you’d expect a higher than normal standard for conviction and sentencing.
The standard estimate is about 10% for the system as a whole.
Literally 100% of people who ever lived have done multiple things which unfriendly legal system might treat as crimes, starting from simple ones like watching youtube videos uploaded without consent of their copyright owners, making mistakes on tax forms, reckless driving, defamation, hate speech, and going as far as the legal system wants to go.
Vast majority of suspects in US do not get any trial whatsoever, they’re forced to accept punishment or risk vastly higher punishment if they want to take their chance of trial.
There are good reasons to believe few trials that happen are extremely far from any kind of fairness, and they’re stacked to give persecution an advantage. Just compare massive funding of police and prosecutors with puny funding of defense attorneys.
US has extraordinarily high number of prisoners per capita. Looking at crime rates alone, it does not have extraordinarily high levels of serious crime per capita. There’s no way most people in prisons can be anything but innocent (or “guilty” of minor and irrelevant “crimes” pretty much everybody is “guilty” of and persecuted on legal system’s whims).
Unless you believe that young black men in US are the most criminal group in history of the world, most of them who are in prisons must be innocent by pure statistics.
Still, I’d bet that at least 99.5% of people alive now have done something which is technically illegal in their jurisdiction. (Not sure about “who ever lived”, though.)
Unless you believe that young black men in US are the most criminal group in history of the world, most of them who are in prisons must be innocent by pure statistics.
This is by far your weakest point.
Men commit more crime than women. Young people commit more crime than the elderly. Black people commit more crime than white people.
Ergo yes young black males are probably one of the most criminal groups in the developed world. I bet Japanese American grandmothers are among the least, I can’t imagine why,but somehow it just seems overwhelmingly likley.
If you want to quibble that government is more likley to make things that men, the young and black people do, illegal feel free to, but considering all three opening statements are also true for violent crimes and that victim reports basically match arrest ratios on all of them. I think all three are blatantly obviously true, but somewhat impolite to state.
Violent crime is something that for understandable reasons catches attention more than say white collar crime. It causes greater psychological distress to notice it or suspect you are vulnerable to it. This translates into greater pressure on politicians to make laws against it and provide law enforcement more resources to target it.
Unless you believe that young black men in US are the most criminal group in history of the world, most of them who are in prisons must be innocent by pure statistics.
Or there is a significant selection bias in the quasi-random selection process known as “arresting people.”
By the way, have you read Bernard Harcourt’s research, which suggests that the “imprisonment” rate in the United States has been constant over time, provided that you count commitment for mental illness as imprisonment. Thus, the recent growth in prison population in the United States reflects the shrinkage in long-term involuntary commitment of the mentally ill. In other words, a lot of the restrictions on the extremely mentally ill that used to be “provided” by dedicated institutions (i.e. mental hospitals) are now “provided” by jails and prisons.
You confuse different parts of the justice system, and your criticism is internally self-contradictory. If everyone who ever lived is guilty of something, then high or racially disparate incarceration rates need not catch innocent people. The fact that this occurs is more an indictment of the laws in place and the people who prosecute them, not the courts that adjudicate them.
Put another way, if breathing were a crime, then everyone convicted of it would in fact be guilty. If there were a lot of black men convicted of it, more so than other races, it would likely be due to different rates of prosecution, given how easy the charge would be to prove this is bad, but it is a criticism of the wrong part of the government. It would be like blaming the mayor for the ineffectiveness of the postal service (the former is the city government, the latter is federal).
Edited to clarify: I am referring to the value of our adversarial method and our rules of evidence / constitutional protections—the mechanics of how a trial works. There is an entirely separate issue of prosecutorial discretion and unequal police enforcement and overly draconian laws, which certainly lead to the problems being discussed here. But the entire purpose of evidence law and courtroom proceedings generally is to determine if the person charged is in fact guilty. It is not to determine if the prosecution is charging the right people or if the laws are just or justly enforced. So this criticism seems misplaced.
Selective prosecution is a problem that can be laid at the prosecutor’s doorstep, and if proven, it’s a basis for acquittal. The problem is that it’s hard to prove, not that the prosecutor and cops aren’t responsible. (See my essay “Threat to advocacy from overdeterrence.”
There’s nothing self-contradictory about my criticism, there are multiple interrelated problems. American legal system is totally broken, it’s not just one easy fix away from sanity.
Fetishization of the concept of being “guilty” is one of these problems.
For example—everybody on less wrong is obviously either “guilty” of conspiracy to commit treason and replace various governments by Friendly AI, or at least “guilty” of helping people directly involved in such conspiracy. That’s a problem.
If someone rounded up whoever on lesswrong happens to be black, and prosecuted them, that’s would be a second problem.
It is self contradictory on its face . Compare these statements:
Literally 100% of people who ever lived have done multiple things which unfriendly legal system might treat as crimes, starting from simple ones like watching youtube videos uploaded without consent of their copyright owners, making mistakes on tax forms, reckless driving, defamation, hate speech, and going as far as the legal system wants to go.
US has extraordinarily high number of prisoners per capita. Looking at crime rates alone, it does not have extraordinarily high levels of serious crime per capita. There’s no way most people in prisons can be anything but innocent (or “guilty” of minor and irrelevant “crimes” pretty much everybody is “guilty” of and persecuted on legal system’s whims).
Unless you believe that young black men in US are the most criminal group in history of the world, most of them who are in prisons must be innocent by pure statistics.
The first statement provides a complete alternative explanation for the second two. It is entirely possible to believe that (A) there are far too many crimes, (B) police and prosecutors are biased against black people, and this fully explains why there are so many black people in prison without a single one of them needing to be innocent. Similarly, you say that, given crime rates and incarceration rates, some people must be innocent. Again, this is undermined by the fact that you say everyone is guilty of something. You just can’t argue that everyone is a criminal, and then argue that high incarceration rates must necessarily be attributable to a high rate of convicting innocent persons. They may both be true, but you have no basis to infer the latter given the former.
To the extent that you disclaim this by saying that people are “guilty” of minor “crimes,” your argument becomes largely circular, and is still not supported by evidence. What percentage of thieves/murderers/rapists/etc. are actually caught? How long are sentences? Combine a higher crime rate with a higher catch rate and longer sentences and you easily get a huge prison population without innocent people being convicted. I don’t claim to know if this is the case, but you do, so you need to back it up.
There are good reasons to believe few trials that happen are extremely far from any kind of fairness, and they’re stacked to give persecution an advantage. Just compare massive funding of police and prosecutors with puny funding of defense attorneys.
You completely confuse “did something for which an unfriendly legal system can find them guilty” and “did something seriously dangerous to others that could sensibly be a reason to lock someone one”.
These are not even remotely close. Essentially everyone is the former, very few people are the latter.
If your point is that there are a lot of people locked up for violating laws that are basically stupid, you’re absolutely right.
But that issue is largely irrelevant to the subject of the primary post, which is the accuracy of courts. If the government bans pot, the purpose of evidence law is to determine whether people are guilty of that crime with accuracy.
In other words, your criticism of the normative value of the American legal system is spot-on; we imprison far more people than we should and we have a lot of stupid statutes. But since this context is a discussion of the accuracy of evidentiary rules and court procedure, your criticism is off-topic.
Is it really off-topic to suggest that looking at the accuracy of the courts may amount to rearranging the deck chairs on the titanic in a context where we’ve basically all agreed that
the courts are not terrible at making accurate determinations of whether a defendant broke a law
The set of laws where penalties can land you in prison are massively inefficient socially and in most people’s minds unjust (when we actually grapple with what the laws are, as opposed to how they are usually applied to people like us, for those of us who are white and not poor).
The system of who is tried versus who makes plea bargains versus who never gets tried is systematically discriminatory against those with little money or middle/upper class social connections, and provides few effective protections against known widespread racial bias on the part of police, prosecutors and judges.
How different is this in principle from TimS’s suggestion about lower hanging fruit within evidentiary procedure, just at a meta level? Or did you consider that off-topic as well?
known widespread racial bias on the part of police, prosecutors and judges.
Can you cite evidence for this?
Most of the evidence for this is based on arguing that P(conviction|African descent) > P(conviction|Eurasian descent) and dismissing anyone who points out that P(guilty|African descent) > P(guilty|Eurasian descent) as a racist.
Most of the evidence for this is based on arguing that P(conviction|African decent) > P(conviction|Eurasian decent)
That is Bayesian evidence that there is a racial bias in the conviction process.
Only if one doesn’t know anything about the base rate.
and dismissing anyone who points out that P(guilty|African decent) > P(guilty|Eurasian decent) as a racist.
(But that isn’t evidence!)
Why not?
Mind you those people are probably being racist. In particular they are ‘pointing out’ rather than, say, hypothesizing.
According to your profile you’re from Australia, so I’m going to give you the benefit of the doubt and assume the above statement is due to all your information about the US being filtered through a politically correct filter.
Only if one doesn’t know anything about the base rate.
No, unless you mean by ‘base rate’ something entirely different to the actual priors I would use when making the update the reverse is true. You need to be able to calculate some prior for the relevant base rate in order to make the update either way.
Why not?
Hey, I was agreeing with you! The reason I did so was that the quoted behavior is a social attack that contains more or less no information that is not orthogonal to the issue.
According to your profile you’re from Australia, so I’m going to give you the benefit of the doubt and assume the above statement is due to all your information about the US being filtered through a politically correct filter.
I’m going to suggest, instead, that you are so (justifiably) fed up with abusive usage of political correctness that you patterned matched my statement onto a far more general position which I would not dream of supporting. My actual semantics of my claim is rather mild. The limitation to a probability would itself be sufficient to make it correct but more important is the emphasis on how the potentially claim is presented. The likely neglect of corrections for socioeconomic status and how that impacts whether the difference is in what kinds of crimes are committed and how much those crimes are the sort that actually get convictions irrespective of guilt.
A relevant datapoint regarding the drug use—the most ridiculous element of America’s absurd legal system: the last relevant study I read (the abstract of) found that contrary to common belief white Americans actually use illegal drugs more than black people. Of course the manner and type of drug use is also on average drastically different.
(I also corrected the word ‘decent’ into ‘descent’. My original reading of the claim you actually described regarding decency made the claim even more racist and also confusing.
Now responding to the suggestion of political correctness based naivete I counter that I am actually far less politically correct than average except when the politically correct beliefs are coincidentally correct. With respect to the topic of race in particular I, like many Australians are far less inclined to hit the berserk button and start throwing around social signalling whenever the topic is mentioned. I hypothesize that this is because we never went and captured a whole bunch of African slaves then have a civil war about it! The ‘black vs white’ divide in Australia is in some ways more similar to the ‘white vs Native American’ divide that you have. That is, the race that the English settlers/conquerors mostly genocided when they arrived. This means that we have a different style of racism here and ‘African’ doesn’t warrant a special case when considering racism towards foreign immigrants.
A relevant datapoint regarding the drug use—the most ridiculous element of America’s absurd legal system: the last relevant study I read (the abstract of) found that contrary to common belief white Americans actually use illegal drugs more than black people.
You might be interested in this thread where Alicorn challenged me on that very claim. (Since I had to update on it, I’m obligated by the terms of my Bayesian novitiate to loudly point it out when someone reiterates my previous prior.)
In gist, white Americans are overrepresented in lifetime illegal drugs use, but black Americans are overrepresented in recent (e.g. last-month) illegal drugs use. This is relevant because you don’t get arrested today for having tried cocaine ten years ago. (In other words, if you’re white you’re more likely to have tried dope, but if you’re black, you’re more likely to have used it in the past month.)
However, proportional to recent illegal drugs use, black Americans are overrepresented in illegal drugs arrests.
That said, the statistics I was able to find did not distinguish arrests for drug possession vs. drug dealing; did not distinguish occasional from heavy users (so long as they’d used within the past month); and did not distinguish among different illegal drugs. They also didn’t control for economic class, which is probably significant in where people choose to obtain and use their illegal drugs, which in turn would have some effect on arrest rates.
They also didn’t control for economic class, which is probably significant in where people choose to obtain and use their illegal drugs, which in turn would have some effect on arrest rates.
They also wouldn’t have controlled for technological and strategic capability. ie. The knowing or being able to find out how to use an anonymous service like silkroad, use a conservative policy when receiving such goods and make use of substances in a way that minimises arrest potential. These days working the basics on thing likes this is easy. Spend several hours with google. Yet it remains the case that which subculture someone is in will drastically influence how much they will end up knowing and caring about minimising risk. (“Rah geeky rationalist skills!”)
Yet it remains the case that which subculture someone is in will drastically influence how much they will end up knowing and caring about minimising risk.
Or willingness to use said techniques. I am routinely contacted, due to my Silk Road page, by people wishing me to explain how to use Tor/Bitcoin/Silk Road (despite the entire page being just that sort of guide!) or to buy stuff on Silk Road for them (seriously? you think I might buy some LSD for a random stranger?). I’ve begun to understand why ESR could feel compelled to write how to ask questions the smart way.
Some (most) people really are just mindboggling bad at knowing when and how to just google something, consolidate the knowledge and practically implement it! Or perhaps we just overestimate our capabilities in this regard relative to the norm.
P(guilty|African decent) > P(guilty|Eurasian decent) alright, but that kind of evidence is easily screened out. For any non-trivial amount of forensic evidence E, P(guilty|E, African descent) ought to be approximately the same as P(guilty|E, Eurasian descent). (For example, if E points toward the defendant being guilty, even though you’d assign a higher prior probability of guilt for a black person than for a white person, you’d assign a higher prior probability of E for a black person than for a white person too, so that in the posterior probabilities those cancel out.)
Is there any evidence than American or any other legal system is significantly better than chance at what it does?
which I would interpret as ‘Is P(Conviction|Guilt) substantially larger than P(Conviction|Innocence)?’ Now, for some crimes such as copyright infringement, P(G) is very close to 1, so P(C|G) cannot be close to 1 simply because then there wouldn’t be enough room in prisons to hold NP(C|G)P(G) people (N being the population—times the mean sentence length, over the mean lifespan, and possibly some other factor of order unity I’m forgetting of), and since P(I) is small, in order for P(C|I) to be much less than P(C|G), P(C and I) = P(C|I)P(I) must be very small.
(Also, we want the system to be unbiased, i.e. P(C|G, brown skin) to be close to P(C|G, pink skin), P(C|G, penis) to be close to P(C|G, vagina), and so on, and so forth. The best way of achieving this would IMO be for all of these numbers to be close to 1, but that’s impossible with the current definition of G and finite capacity of prisons.)
which I would interpret as ‘Is P(Conviction|Guilt) substantially larger than P(Conviction|Innocence)?’ Now, for some crimes such as copyright infringement, P(G) is very close to 1, so P(C|G) cannot be close to 1 simply because then there wouldn’t be enough room in prisons to hold NP(C|G)P(G) people (N being the population—times the mean sentence length, over the mean lifespan, and possibly some other factor of order unity I’m forgetting of), and since P(I) is small, in order for P(C|I) to be much less than P(C|G), P(C and I) = P(C|I)P(I) must be very small.
It should be noted that the reasonable meaning of ‘substantially’ in such a case is relative not just the unadorned absolute difference in the ridiculously low probabilities. In comparisons of this nature a difference it is overwhelmingly obvious that “0.0001 − 0.000001” is much more significant than “0.6001 − 0.600001″.
The above consideration is even more important when the substitution of “is significantly better than chance” with “‘Is P(Conviction|Guilt) substantially larger than P(Conviction|Innocence)?’” is yours and not the original question.
It should be noted that the reasonable meaning of ‘substantially’ in such a case is relative not just the unadorned absolute difference in the ridiculously low probabilities. In comparisons of this nature a difference it is overwhelmingly obvious that “0.0001 − 0.000001” is much more significant than “0.6001 − 0.600001″.
I’m not sure of this: I’d very much prefer a world where 0.01% of guilty people and 0.0001 of innocent people are convicted to one where 60.01% and 60.001% are. (If convicting a guilty person has utility A and convicting an innocent person has utility -B, what you want to maximise is AP(C|G) - BP(C|I), which also depends on the magnitudes of the probabilities, not only on their ratio.)
The above consideration is even more important when the substitution of “is significantly better than chance” with “‘Is P(Conviction|Guilt) substantially larger than P(Conviction|Innocence)?’” is yours and not the original question.
Huh? How else could the original question be interpreted? [ETA: Well, if better is interpreted instrumentally rather than epistemically, “the legal system is significantly better than chance” means “AP(C|G) - BP(C|I) is significantly greater than AP(C) - BP(C)”; and since A is orders of magnitude less than B (unless we’re talking about serial killers or similarly serious stuff), that boils down to “P(C|I) is significantly less than P(C)”, where it’s the magnitude of the difference that matters, rather than the ratio.]
I’m not sure of this: I’d very much prefer a world where 0.01% of guilty people and 0.0001 of innocent people are convicted to one where 60.01% and 60.001% are.
So do I. This answers the question “do I consider false convictions worse than guilty parties who are not punished” but does not tell us much about the original question. The point of the original question was not “with trivial consideration of how much the conviction process is different to chance how high is the base rate of convictions for this crime?”
Huh? How else could the original question be interpreted?
That is a reasonable interpretation—the point is that we must also interpret ‘significance’ in light of the original meaning. That original meaning does not contain an overwhelming emphasis on the base rate of convictions!
The immediately obvious answer would be “over the prosecuted if you’re only ‘testing’ the courtroom itself, over all the people if you’re ‘testing’ the whole system”, but I’m not sure what the ‘ideal’ thing for a courtroom to do in terms of P(C|Prosecution, G) and P(C|P,I) if the police is ‘non-ideal’ so that P(P|G) is not close to or greater than P(P|I) to start with. Or even whether this question makes sense… I’ll have to think more clearly about this when I’m not this tired.
Looking at crime rates alone, it does not have extraordinarily high levels of serious crime per capita.
Doesn’t it? I remember gun control arguments from years back where people would note the US’s high murder rate compared to Canada and other similar countries with more restricted gun ownership. Then someone would bring up Switzerland which has wide gun ownership and low crime.
I would consider the US rate high, it’s around 4 times that of Australia or Western and Central Europe, 3 times that of Canada, and over 2.5 times that of New Zealand, but agreed it’s not that relevant.
A but of hyperbole, perhaps. Nonetheless, it is all but certain that the overwhelming majority of Americans (100% - epsilon would not surprise me) over the age of responsibility (~7 years old) have committed a felony.
An unfriendly legal system might treat being born as a crime. In fact, I’d be surprised if some politician in Arizona hasn’t tried to make being born to illegal immigrant parents a crime.
The downvotes surprise me, because the rhetoric is precisely along these lines, e.g. Sonny Bono wanting to remove state benefits from the US-born children of illegal immigrants on the justification “they’re illegal”. Illegal people.
Yeah, I was wondering about the downvotes. The welcome thread says that it’s perfectly acceptable to ask for an explanation… So, for anyone who downvoted me, why?
It seems to me that even children that young have generally done various sorts of property damage and assault, and that most excuses for that behavior will rest on not considering them “people”.
An adult with the behavior of a very young child would be declared irresponsible by psychiatrists, and thus couldn’t be tried (but could be arrested and committed). It seems reasonable to apply this to children, and they are automatically committed to restrictive institutions already.
I agree with most of what you say, but I’m not so sure about the last two. As others have pointed out, there are many, many cases where the primary suspect of a crime is never prosecuted. Given a choice, prosecutors will usually choose “easy” cases. So an alternate explanation for America’s high prison population and incredibly high black prison population is that
more criminals are prosecuted and convicted in America, and
jurors are biased and black criminals are therefore easier to convict; and/or prosecutors are biased and therefore prosecute more black criminals.
Now, since I don’t think it’s actually optimal for everyone who ever breaks a law to be punished, I have no problem saying, for example, “More criminals are prosecuted and convicted here, and that’s too bad.”
US has extraordinarily high number of prisoners per capita. Looking at crime rates alone, it does not have extraordinarily high levels of serious crime per capita. There’s no way most people in prisons can be anything but innocent (or “guilty” of minor and irrelevant “crimes” pretty much everybody is “guilty” of and persecuted on legal system’s whims).
Unless you believe that young black men in US are the most criminal group in history of the world, most of them who are in prisons must be innocent by pure statistics.
This doesn’t follow. You could believe that other groups have higher rates of criminality, but are underimprisoned relative to their rate of guilt.
There are good reasons to believe few trials that happen are extremely far from any kind of fairness, and they’re stacked to give persecution an advantage. Just compare massive funding of police and prosecutors with puny funding of defense attorneys.
On the other hand, the prosecution needs to convince twelve jurors, the defense only needs to convince one.
On the other hand, the prosecution needs to convince twelve jurors, the defense only needs to convince one.
Not necessarily. If the 11 and the 1 hold fast, then this results in a mistrial, not an acquittal; so really the defence needs to convince only 1 but every time, while the prosecution needs to convince all 12 but only once. (And in fact the 1 will be under enormous pressure from the 11 to convert before that point is reached.) ETA: Of course ‘every time’ is not forever; eventually the prosecution will give up.
By “better than chance” do you mean whether when investigating e.g. a murder, the American police and legal system have more than P(1/population of America) of locating and punishing the actual guilty party?
Is there any evidence than American or any other legal system is significantly better than chance at what it does? Or even not significantly worse than chance? (by being biased instead of just random)
That’s the first question we should be asking, before concerning ourselves with minor issues about admissibility of evidence.
That’s an excellent question. The answer depends on exactly what you mean by “better than chance.” If you mean “more than half of those convicted of a crime are guilty of that crime,” then I’d say yes, there is excellent reason to think that they are. Prosecutors usually have access to several times more reports of crime than they can afford to go out and prosecute. Prosecutors are often explicitly or implicitly evaluated on their win ratio—they have strong incentives to pick the ‘easy’ cases where there is abundant evidence that the suspect is guilty. Most defense lawyers will cheerfully concede that the vast majority of their clients are guilty—either the clients admit as much to their lawyers, or the clients insist on implausible stories that don’t pass muster, which the lawyers have to disguise in order to get their clients to go free. Although as a matter of law and rhetoric people are presumed innocent until proven guilty, as a matter of cold statistics, someone who has been lawfully indicted in America is probably more likely to be guilty than innocent. In fact, there are probably so many guilty suspects in Court that the legal system does strictly worse than what social scientists call a “naive predictor”—i.e., just assuming that everyone is guilty. Of course, that wouldn’t be a sustainable policy—prosecutors choose easy cases because they know that they’ll be required to win those cases in a relatively challenging environment. If the rule were that everyone is guilty, prosecutors would start choosing cases based on other criteria, and the percentage of indicted suspects who were actually guilty would go down.
Suppose you survey defense attorneys, and conclude that, say, roughly 80% of indicted suspects are guilty. Could you somehow measure whether the legal system does better than a “mixed strategy predictor” that guessed that a suspect was guilty with probability 0.8 and guessed that a suspect was innocent with probability 0.2? The mixed-strategy predictor would get an accurate result in (0.8) ^ 2 + (0.2) ^ 2 = 68% of the time. To assess whether the legal system is better than a mixed-strategy predictor, you would need to have a way of validating at least a sample of actual cases. I really have no idea how you would start to do that. It’s not clear that self-reported guilt or defense-attorney-assessed guilt will correlate strongly enough with actual guilt that we can figure out which individual cases the legal system gets right and which ones it gets wrong. But if you can’t measure accuracy in individual cases, how do you figure out the system’s overall accuracy rate? It’s not clear that looking at appellate results or DNA exonerations, etc. would help either. A reversal on appeal is no guarantee of innocence, because a sentence can be reversed (a) if the evidence is still strong but not strong enough to remove all reasonable doubt as well as (b) when the prosecution or police have used inappropriate but reliable tactics (such as using high-tech cameras to take pictures of the inside of your home without a warrant).
Finally, there is “better than chance” in the sense of specific forensic techniques being verifiably better than, say, a Ouija board. There are several pretty good techniques, such as document analysis, DNA analysis, electronic tracing, and perhaps even paired-question polygraph testing. Whether or not the system interprets the evidence correctly, a typical trial at least contains sufficient evidence for a rational evaluator to beat chance.
Careful, there: the economic damage of not locking up a thief is much lower than the economic damage of incorrectly locking up a non-thief. “It’s better that X guilty people go free than that one innocent person goes to prison” is a good principle.
(Note that X is likely to have different values for weed users, thieves and serial killers.)
Worse epistemically, not instrumentally.
Could you expand on that?
I’ll have a go.
A thief at large but constrained by trying not to get caught doesn’t do as much net economic damage as destroying the economic, family and social life of an otherwise productive member of society.
For example, it would be almost impossible for a single shoplifter or casual stealer of office supplies to do anything like the economic damage of even removing themselves from the economy and putting them in prison. The only reason we still do it is to discourage behaviour that would seriously hurt the economy if it became the norm.
If you start locking people up with careless disregard for whether or not they are guilty, you get all the economic cost of the prison system but lose the clarity of the signal. The message becomes “hey, you’re probably going to prison at some point anyway. Might as well grab what you can while you are still free to enjoy it”.
I wouldn’t quite expect that, but certainly I agree that if there’s no expectation that punishment correlates better with committing a crime than with refraining from doing so, then punishment loses its deterrent function, which I gather is your real point here.
Part of my point.
In addition to that, perception of unfairness in the justice system devalues the social contract between government and individuals. It places the individual in a competing rather than cooperating relationship with social institutions (such as law enforcement), so it’s not a mere lack of deterrence, it’s active encouragement to defect for individual gain at the expense of “the man”.
If you doubt it, ask anyone who lives in a neighbourhood where the cops have a record of incompetence or abuse of authority.
I’ve heard (anecdotally, not with good evidence) that this is precisely the attitude that many poor urban young black men already have (actually with ‘go to prison’ changed to ‘go to prison or get killed’). Thus one has every reason to join a gang for the immediate services that it provides, future be damned.
If a random 80% of suspects are guilty, the appropriate naive predictor is one that always votes “guilty”, not one that tries to match probabilities by choosing a random 80% of suspects to call guilty. Then you get an accurate result 80% of the time, which is a lot better than 68%. That seems to me a more appropriate benchmark.
(Alternatively, you might consider a predictor that matches its probabilities not to the proportion of defendants who are guilty but to the proportion who are convicted. There might be something to be said for that.)
I think the intended question is whether the legal system adds anything beyond a pure chance element. Somehow we’d need a gold standard of actually guilty and innocent suspects, then we’d need to measure whether p(guilty|convicted) > 80%. You could also ask if p(innocent|acquitted) > 20%, but that’s the same question.
Thank you! Intended or not, it’s a fantastic question, and I don’t know where to look up the answer. I’m not even sure that anyone has seriously tried to answer that question. If they haven’t, then I want to. I’ll look into it.
The closest thing I know of is the “actually innocent, but convicted” sample that gradually came to light under DNA testing of inmates. Unreported crime rates get estimated somehow, so I’d be surprised if nobody had combined those numbers to do a study in this vein. Haven’t found one with a cursory googling, though.
I don’t see how those are “the same question”. If out of 8 accused 4 are guilty and two of them are convicted, the rest acquitted. Than p(guilty|convicted) = 1 and p(innocent|acquitted) = 2⁄3.
The assumption was that 80% of defendants are guilty, which is more than 4 of 8. Under this assumption, asking whether p(guilty|convicted) > 80% is just asking whether conviction positively correlates with guilt. Asking if p(innocent|acquitted) > 20% is just asking if acquittal positively correlates with innocence. These are really the same question, because P correlates with Q iff ¬P correlates with ¬Q.
Perfect. Thanks.
I’m sorry, but I can’t produce any response but bewilderment. You think DNA exonerations don’t give evidence about the accuracy of the system? Really?
It proves that mistakes have been made, but in the end, no, I don’t think it’s terribly useful evidence for evaluating the rate of wrongful convictions. Why not? There have been 289 post-conviction DNA exonerations in US history, mostly in the last 15 years. That gives a rate of under 20 per year. Suppose 10,000 people a year are incarcerated for the types of crime that DNA exoneration is most likely to be possible for, namely murder and rape (I couldn’t find exact figures, but I suspect the real number is at least this big). Then considering DNA exonerations gives us a lower bound of something like .2% on the error rate of US courts.
That is only useful evidence about the error rate if your prior estimate of the inaccuracy was less than that, and I mean, come on, really? Only one conviction in 500 is a mistake?
DNA exoneration happens when one is innocent and combination of extremely lucky circumstances make retesting of evidence possible. The latter I would be shocked to find at higher than 1:100 chance.
The appellate system itself—of which cases involving new DNA evidence are a tiny fraction—is a much more useful measure.
There are a whole lot more exonerations via the appeals process than those driven by DNA evidence alone. This aught to be obvious, and the 0.2% provided by DNA is an extreme lower bound, not the actual rate of error correction.
Case in point, I found an article describing a study on overturning death penalty convictions, and they found that 7% of convictions were overturned on re-trial, and 75% of sentences were reduced from the death penalty upon re-trial.
One in fourteen sounds a lot more reasonable to me, and again that’s just death penalty cases, for which you’d expect a higher than normal standard for conviction and sentencing.
The standard estimate is about 10% for the system as a whole.
A few observations:
Literally 100% of people who ever lived have done multiple things which unfriendly legal system might treat as crimes, starting from simple ones like watching youtube videos uploaded without consent of their copyright owners, making mistakes on tax forms, reckless driving, defamation, hate speech, and going as far as the legal system wants to go.
Vast majority of suspects in US do not get any trial whatsoever, they’re forced to accept punishment or risk vastly higher punishment if they want to take their chance of trial.
There are good reasons to believe few trials that happen are extremely far from any kind of fairness, and they’re stacked to give persecution an advantage. Just compare massive funding of police and prosecutors with puny funding of defense attorneys.
US has extraordinarily high number of prisoners per capita. Looking at crime rates alone, it does not have extraordinarily high levels of serious crime per capita. There’s no way most people in prisons can be anything but innocent (or “guilty” of minor and irrelevant “crimes” pretty much everybody is “guilty” of and persecuted on legal system’s whims).
Unless you believe that young black men in US are the most criminal group in history of the world, most of them who are in prisons must be innocent by pure statistics.
Entirely for the sake of being pedantic, I’ll point out that many people have avoided this, if only by dying very shortly after being born.
taw was only reporting to one significant digit :P
I see three.
100.% (with a decimal before the percent sign) would be three. 100% with no decimal is one.
I’d consider numbers such as “100” to be ambiguous between one, two or three significant digits. As for “literally”...
Still, I’d bet that at least 99.5% of people alive now have done something which is technically illegal in their jurisdiction. (Not sure about “who ever lived”, though.)
This is by far your weakest point.
Men commit more crime than women. Young people commit more crime than the elderly. Black people commit more crime than white people.
Ergo yes young black males are probably one of the most criminal groups in the developed world. I bet Japanese American grandmothers are among the least, I can’t imagine why,but somehow it just seems overwhelmingly likley.
If you want to quibble that government is more likley to make things that men, the young and black people do, illegal feel free to, but considering all three opening statements are also true for violent crimes and that victim reports basically match arrest ratios on all of them. I think all three are blatantly obviously true, but somewhat impolite to state.
Violent crime is something that for understandable reasons catches attention more than say white collar crime. It causes greater psychological distress to notice it or suspect you are vulnerable to it. This translates into greater pressure on politicians to make laws against it and provide law enforcement more resources to target it.
Or there is a significant selection bias in the quasi-random selection process known as “arresting people.”
By the way, have you read Bernard Harcourt’s research, which suggests that the “imprisonment” rate in the United States has been constant over time, provided that you count commitment for mental illness as imprisonment. Thus, the recent growth in prison population in the United States reflects the shrinkage in long-term involuntary commitment of the mentally ill. In other words, a lot of the restrictions on the extremely mentally ill that used to be “provided” by dedicated institutions (i.e. mental hospitals) are now “provided” by jails and prisons.
You confuse different parts of the justice system, and your criticism is internally self-contradictory. If everyone who ever lived is guilty of something, then high or racially disparate incarceration rates need not catch innocent people. The fact that this occurs is more an indictment of the laws in place and the people who prosecute them, not the courts that adjudicate them.
Put another way, if breathing were a crime, then everyone convicted of it would in fact be guilty. If there were a lot of black men convicted of it, more so than other races, it would likely be due to different rates of prosecution, given how easy the charge would be to prove this is bad, but it is a criticism of the wrong part of the government. It would be like blaming the mayor for the ineffectiveness of the postal service (the former is the city government, the latter is federal).
Edited to clarify: I am referring to the value of our adversarial method and our rules of evidence / constitutional protections—the mechanics of how a trial works. There is an entirely separate issue of prosecutorial discretion and unequal police enforcement and overly draconian laws, which certainly lead to the problems being discussed here. But the entire purpose of evidence law and courtroom proceedings generally is to determine if the person charged is in fact guilty. It is not to determine if the prosecution is charging the right people or if the laws are just or justly enforced. So this criticism seems misplaced.
Selective prosecution is a problem that can be laid at the prosecutor’s doorstep, and if proven, it’s a basis for acquittal. The problem is that it’s hard to prove, not that the prosecutor and cops aren’t responsible. (See my essay “Threat to advocacy from overdeterrence.”
If a bad law is applied in a racist way, surely that’s a problem with both the law itself and the justice system’s enforcement of it?
There’s nothing self-contradictory about my criticism, there are multiple interrelated problems. American legal system is totally broken, it’s not just one easy fix away from sanity.
Fetishization of the concept of being “guilty” is one of these problems.
For example—everybody on less wrong is obviously either “guilty” of conspiracy to commit treason and replace various governments by Friendly AI, or at least “guilty” of helping people directly involved in such conspiracy. That’s a problem.
If someone rounded up whoever on lesswrong happens to be black, and prosecuted them, that’s would be a second problem.
It is self contradictory on its face . Compare these statements:
The first statement provides a complete alternative explanation for the second two. It is entirely possible to believe that (A) there are far too many crimes, (B) police and prosecutors are biased against black people, and this fully explains why there are so many black people in prison without a single one of them needing to be innocent. Similarly, you say that, given crime rates and incarceration rates, some people must be innocent. Again, this is undermined by the fact that you say everyone is guilty of something. You just can’t argue that everyone is a criminal, and then argue that high incarceration rates must necessarily be attributable to a high rate of convicting innocent persons. They may both be true, but you have no basis to infer the latter given the former.
To the extent that you disclaim this by saying that people are “guilty” of minor “crimes,” your argument becomes largely circular, and is still not supported by evidence. What percentage of thieves/murderers/rapists/etc. are actually caught? How long are sentences? Combine a higher crime rate with a higher catch rate and longer sentences and you easily get a huge prison population without innocent people being convicted. I don’t claim to know if this is the case, but you do, so you need to back it up.
There are good reasons to believe few trials that happen are extremely far from any kind of fairness, and they’re stacked to give persecution an advantage. Just compare massive funding of police and prosecutors with puny funding of defense attorneys.
You completely confuse “did something for which an unfriendly legal system can find them guilty” and “did something seriously dangerous to others that could sensibly be a reason to lock someone one”.
These are not even remotely close. Essentially everyone is the former, very few people are the latter.
If your point is that there are a lot of people locked up for violating laws that are basically stupid, you’re absolutely right.
But that issue is largely irrelevant to the subject of the primary post, which is the accuracy of courts. If the government bans pot, the purpose of evidence law is to determine whether people are guilty of that crime with accuracy.
In other words, your criticism of the normative value of the American legal system is spot-on; we imprison far more people than we should and we have a lot of stupid statutes. But since this context is a discussion of the accuracy of evidentiary rules and court procedure, your criticism is off-topic.
Is it really off-topic to suggest that looking at the accuracy of the courts may amount to rearranging the deck chairs on the titanic in a context where we’ve basically all agreed that
the courts are not terrible at making accurate determinations of whether a defendant broke a law
The set of laws where penalties can land you in prison are massively inefficient socially and in most people’s minds unjust (when we actually grapple with what the laws are, as opposed to how they are usually applied to people like us, for those of us who are white and not poor).
The system of who is tried versus who makes plea bargains versus who never gets tried is systematically discriminatory against those with little money or middle/upper class social connections, and provides few effective protections against known widespread racial bias on the part of police, prosecutors and judges.
How different is this in principle from TimS’s suggestion about lower hanging fruit within evidentiary procedure, just at a meta level? Or did you consider that off-topic as well?
Can you cite evidence for this?
Most of the evidence for this is based on arguing that P(conviction|African descent) > P(conviction|Eurasian descent) and dismissing anyone who points out that P(guilty|African descent) > P(guilty|Eurasian descent) as a racist.
(Or even do the homophone and ‘cite’?)
That is Bayesian evidence that there is a racial bias in the conviction process.
(But that isn’t evidence!)
Mind you those people are probably being racist. In particular they are ‘pointing out’ rather than, say, hypothesizing.
Thanks fixed.
Only if one doesn’t know anything about the base rate.
Why not?
According to your profile you’re from Australia, so I’m going to give you the benefit of the doubt and assume the above statement is due to all your information about the US being filtered through a politically correct filter.
No, unless you mean by ‘base rate’ something entirely different to the actual priors I would use when making the update the reverse is true. You need to be able to calculate some prior for the relevant base rate in order to make the update either way.
Hey, I was agreeing with you! The reason I did so was that the quoted behavior is a social attack that contains more or less no information that is not orthogonal to the issue.
I’m going to suggest, instead, that you are so (justifiably) fed up with abusive usage of political correctness that you patterned matched my statement onto a far more general position which I would not dream of supporting. My actual semantics of my claim is rather mild. The limitation to a probability would itself be sufficient to make it correct but more important is the emphasis on how the potentially claim is presented. The likely neglect of corrections for socioeconomic status and how that impacts whether the difference is in what kinds of crimes are committed and how much those crimes are the sort that actually get convictions irrespective of guilt.
A relevant datapoint regarding the drug use—the most ridiculous element of America’s absurd legal system: the last relevant study I read (the abstract of) found that contrary to common belief white Americans actually use illegal drugs more than black people. Of course the manner and type of drug use is also on average drastically different.
(I also corrected the word ‘decent’ into ‘descent’. My original reading of the claim you actually described regarding decency made the claim even more racist and also confusing.
Now responding to the suggestion of political correctness based naivete I counter that I am actually far less politically correct than average except when the politically correct beliefs are coincidentally correct. With respect to the topic of race in particular I, like many Australians are far less inclined to hit the berserk button and start throwing around social signalling whenever the topic is mentioned. I hypothesize that this is because we never went and captured a whole bunch of African slaves then have a civil war about it! The ‘black vs white’ divide in Australia is in some ways more similar to the ‘white vs Native American’ divide that you have. That is, the race that the English settlers/conquerors mostly genocided when they arrived. This means that we have a different style of racism here and ‘African’ doesn’t warrant a special case when considering racism towards foreign immigrants.
You might be interested in this thread where Alicorn challenged me on that very claim. (Since I had to update on it, I’m obligated by the terms of my Bayesian novitiate to loudly point it out when someone reiterates my previous prior.)
In gist, white Americans are overrepresented in lifetime illegal drugs use, but black Americans are overrepresented in recent (e.g. last-month) illegal drugs use. This is relevant because you don’t get arrested today for having tried cocaine ten years ago. (In other words, if you’re white you’re more likely to have tried dope, but if you’re black, you’re more likely to have used it in the past month.)
However, proportional to recent illegal drugs use, black Americans are overrepresented in illegal drugs arrests.
That said, the statistics I was able to find did not distinguish arrests for drug possession vs. drug dealing; did not distinguish occasional from heavy users (so long as they’d used within the past month); and did not distinguish among different illegal drugs. They also didn’t control for economic class, which is probably significant in where people choose to obtain and use their illegal drugs, which in turn would have some effect on arrest rates.
They also wouldn’t have controlled for technological and strategic capability. ie. The knowing or being able to find out how to use an anonymous service like silkroad, use a conservative policy when receiving such goods and make use of substances in a way that minimises arrest potential. These days working the basics on thing likes this is easy. Spend several hours with google. Yet it remains the case that which subculture someone is in will drastically influence how much they will end up knowing and caring about minimising risk. (“Rah geeky rationalist skills!”)
Or willingness to use said techniques. I am routinely contacted, due to my Silk Road page, by people wishing me to explain how to use Tor/Bitcoin/Silk Road (despite the entire page being just that sort of guide!) or to buy stuff on Silk Road for them (seriously? you think I might buy some LSD for a random stranger?). I’ve begun to understand why ESR could feel compelled to write how to ask questions the smart way.
Some (most) people really are just mindboggling bad at knowing when and how to just google something, consolidate the knowledge and practically implement it! Or perhaps we just overestimate our capabilities in this regard relative to the norm.
P(guilty|African decent) > P(guilty|Eurasian decent) alright, but that kind of evidence is easily screened out. For any non-trivial amount of forensic evidence E, P(guilty|E, African descent) ought to be approximately the same as P(guilty|E, Eurasian descent). (For example, if E points toward the defendant being guilty, even though you’d assign a higher prior probability of guilt for a black person than for a white person, you’d assign a higher prior probability of E for a black person than for a white person too, so that in the posterior probabilities those cancel out.)
Agreed, however, I fail to see what this has to do with my point.
Never mind. I had misunderstood your point.
The original question was:
which I would interpret as ‘Is P(Conviction|Guilt) substantially larger than P(Conviction|Innocence)?’ Now, for some crimes such as copyright infringement, P(G) is very close to 1, so P(C|G) cannot be close to 1 simply because then there wouldn’t be enough room in prisons to hold NP(C|G)P(G) people (N being the population—times the mean sentence length, over the mean lifespan, and possibly some other factor of order unity I’m forgetting of), and since P(I) is small, in order for P(C|I) to be much less than P(C|G), P(C and I) = P(C|I)P(I) must be very small.
(Also, we want the system to be unbiased, i.e. P(C|G, brown skin) to be close to P(C|G, pink skin), P(C|G, penis) to be close to P(C|G, vagina), and so on, and so forth. The best way of achieving this would IMO be for all of these numbers to be close to 1, but that’s impossible with the current definition of G and finite capacity of prisons.)
It should be noted that the reasonable meaning of ‘substantially’ in such a case is relative not just the unadorned absolute difference in the ridiculously low probabilities. In comparisons of this nature a difference it is overwhelmingly obvious that “0.0001 − 0.000001” is much more significant than “0.6001 − 0.600001″.
The above consideration is even more important when the substitution of “is significantly better than chance” with “‘Is P(Conviction|Guilt) substantially larger than P(Conviction|Innocence)?’” is yours and not the original question.
I’m not sure of this: I’d very much prefer a world where 0.01% of guilty people and 0.0001 of innocent people are convicted to one where 60.01% and 60.001% are. (If convicting a guilty person has utility A and convicting an innocent person has utility -B, what you want to maximise is AP(C|G) - BP(C|I), which also depends on the magnitudes of the probabilities, not only on their ratio.)
Huh? How else could the original question be interpreted? [ETA: Well, if better is interpreted instrumentally rather than epistemically, “the legal system is significantly better than chance” means “AP(C|G) - BP(C|I) is significantly greater than AP(C) - BP(C)”; and since A is orders of magnitude less than B (unless we’re talking about serial killers or similarly serious stuff), that boils down to “P(C|I) is significantly less than P(C)”, where it’s the magnitude of the difference that matters, rather than the ratio.]
So do I. This answers the question “do I consider false convictions worse than guilty parties who are not punished” but does not tell us much about the original question. The point of the original question was not “with trivial consideration of how much the conviction process is different to chance how high is the base rate of convictions for this crime?”
That is a reasonable interpretation—the point is that we must also interpret ‘significance’ in light of the original meaning. That original meaning does not contain an overwhelming emphasis on the base rate of convictions!
Are we restricting to cases that are prosecuted or doing this over all people?
The immediately obvious answer would be “over the prosecuted if you’re only ‘testing’ the courtroom itself, over all the people if you’re ‘testing’ the whole system”, but I’m not sure what the ‘ideal’ thing for a courtroom to do in terms of P(C|Prosecution, G) and P(C|P,I) if the police is ‘non-ideal’ so that P(P|G) is not close to or greater than P(P|I) to start with. Or even whether this question makes sense… I’ll have to think more clearly about this when I’m not this tired.
Doesn’t it? I remember gun control arguments from years back where people would note the US’s high murder rate compared to Canada and other similar countries with more restricted gun ownership. Then someone would bring up Switzerland which has wide gun ownership and low crime.
Homicide rates by country. US has higher homicide rate than Europe but nothing unusual.
Switzerland only has high gun “ownership” when you include military weapons with sealed ammo nobody is allowed to use in their own free time outside regulated places. Recently they don’t even give people sealed ammo. And rifles in any case are pretty useless in crimes, just as are hunting guns (see Canada). Handgun ownership is the key statistics, and that’s why US has higher violent crime rate, which is pretty immaterial here anyway since vast majority of prisoners are there for non-violent crimes.
Thanks for the link to homicide rates, upvoted.
I would consider the US rate high, it’s around 4 times that of Australia or Western and Central Europe, 3 times that of Canada, and over 2.5 times that of New Zealand, but agreed it’s not that relevant.
IAWYC, but
Seriously? How many crimes has someone dying at the age of 1 committed in average?
Being a public nuisance.
Destruction of their parents’ property.
Kicking their mom can probably be classified as domestic violence.
Edited to add: Also biting.
A but of hyperbole, perhaps. Nonetheless, it is all but certain that the overwhelming majority of Americans (100% - epsilon would not surprise me) over the age of responsibility (~7 years old) have committed a felony.
An unfriendly legal system might treat being born as a crime. In fact, I’d be surprised if some politician in Arizona hasn’t tried to make being born to illegal immigrant parents a crime.
The downvotes surprise me, because the rhetoric is precisely along these lines, e.g. Sonny Bono wanting to remove state benefits from the US-born children of illegal immigrants on the justification “they’re illegal”. Illegal people.
Yeah, I was wondering about the downvotes. The welcome thread says that it’s perfectly acceptable to ask for an explanation… So, for anyone who downvoted me, why?
Didn’t downvote, but I think your comment visually matches the ‘strawman argument’ pattern. Except that it is not.
[citation please]
It seems to me that even children that young have generally done various sorts of property damage and assault, and that most excuses for that behavior will rest on not considering them “people”.
An adult with the behavior of a very young child would be declared irresponsible by psychiatrists, and thus couldn’t be tried (but could be arrested and committed). It seems reasonable to apply this to children, and they are automatically committed to restrictive institutions already.
A 1 year old not many yet, but in US police has been increasingly used even against elementary school children, so 1 year olds are not safe forever.
This book seems relevant.
I agree with most of what you say, but I’m not so sure about the last two. As others have pointed out, there are many, many cases where the primary suspect of a crime is never prosecuted. Given a choice, prosecutors will usually choose “easy” cases. So an alternate explanation for America’s high prison population and incredibly high black prison population is that
more criminals are prosecuted and convicted in America, and
jurors are biased and black criminals are therefore easier to convict; and/or prosecutors are biased and therefore prosecute more black criminals.
Now, since I don’t think it’s actually optimal for everyone who ever breaks a law to be punished, I have no problem saying, for example, “More criminals are prosecuted and convicted here, and that’s too bad.”
This doesn’t follow. You could believe that other groups have higher rates of criminality, but are underimprisoned relative to their rate of guilt.
On the other hand, the prosecution needs to convince twelve jurors, the defense only needs to convince one.
Not necessarily. If the 11 and the 1 hold fast, then this results in a mistrial, not an acquittal; so really the defence needs to convince only 1 but every time, while the prosecution needs to convince all 12 but only once. (And in fact the 1 will be under enormous pressure from the 11 to convert before that point is reached.) ETA: Of course ‘every time’ is not forever; eventually the prosecution will give up.
By “better than chance” do you mean whether when investigating e.g. a murder, the American police and legal system have more than P(1/population of America) of locating and punishing the actual guilty party?